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Editorial Guidelines

Creators: Sean Gillies, Jeffrey Becker, Elizabeth Robinson, Adam Rabinowitz, Tom Elliott, Sarah Bond, Brian Turner, Stuart Dunn, Noah Kaye, Ryan Horne Copyright © The Contributors. Sharing and remixing permitted under terms of the Creative Commons Attribution 3.0 License (cc-by).
Last modified Jun 07, 2020 05:51 AM
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Detailed policy instructions for the creation and editing of place, name, location, and connection resources in Pleiades.


Note that content entered in Pleiades prior to November 2016, as well as data more recently imported from other databases, may deviate from guidance here. Contributors are encouraged to undertake and submit updates that bring existing references into conformance with these Guidelines. 

Conceptual Overview

Pleiades uses the terms "place," "name," "location," and "connection" in specific, deliberate ways. Understanding the definitions of each is essential to making the most of Pleiades, especially as a contributor of new and updated content. A separate document -- the Pleiades Conceptual Overview -- explains the distinctions. Reading it first is highly recommended.

Database Structure

The Pleiades system documents and describes each of these four conceptual entities (places, names, locations, and entities) using a corresponding information resource. Information resources are bundles of structured data that are similar in function to records in a database or index cards in a card file. Each place resource contains the name, location, and connection resources with which it is associated. This encapsulation is expressed in the layout of information on the Pleiades website, and in the hierarchical structure of the Uniform Resource Identifiers (URIs: web addresses) assigned to each resource. Each place resource has a corresponding web page in Pleiades, and each place page links to individual pages for all the name, location, and connection resources that have been associated with it.

The structure and implementation of the Pleiades database are described in more detail in the Pleiades Data Model document.

About Titles

The Pleiades information resource for each place, location, name, or connection always includes a title, but each type of entity has different titling conventions. A place may have multiple names at different points in time, and a name may have multiple Romanizations, but the place resource and each of the associated name resources receives only one title each. Similarly, each location has only one title, but there are several different types of location in Pleiades, and conventions for titling differ between them. Policy and examples for each case are provided below. In general, punctuation (commas, periods, apostrophes) should be avoided wherever possible in titles (so “Arch of Trajan”, rather than “Trajan’s Arch”).

When a commonly used modern proper name is seen to be erroneous or otherwise misleading (e.g., when a tomb is imaginatively assigned to a famous historical figure), contributors and editors may choose to relegate this information to a “summary” or “details” field, and add the words “so-called,” surround the proper name in quotation marks, or otherwise caveat the information. This preserves searchability, but avoids specious repetition of incorrect information.

About Summaries (Descriptions)

All resources in Pleiades have "summary" fields (sometimes called "descriptions"). The contents of these fields are intended to facilitate discovery of Pleiades content and disambiguation of same-titled items in search results and map pop-ups. Summaries should be concise and less than 300 characters in length (including spaces). They must be plain-text (i.e., no italics, bold, links, or other formatting). Longer descriptive statements should appear in the “details” field of the relevant resource (q.v.).

The editors’ expectations regarding the content of summaries varies between place, location, name, and connection resources. In general, the summary field for locations must reflect only information about the coordinates themselves (scale, source, reason for choice, etc.). Similarly, name summaries should confine themselves to summary information concerning the name and its sources. Summary information concerning the things represented (e.g., the city or monument or building) should be placed in the “summary” or “details” field on the associated place resource. Additional specific guidance is provided in the appropriate sections below.

About Dates

Pleiades places exist independently of time and contain no temporal information themselves. Temporal information is applied to the locations, names, and connections with which a place is associated. This approach, which is reflected in the data structure of the corresponding information resources, gives Pleiades users the flexibility necessary to model the known temporal distribution of the individual names for a place; to identify (wherever possible) the age and longevity of the various spatial features that constitute its locations; and to constrain relationships between places to particular periods. Pleiades uses a heterogenous and growing list of named time periods when assigning individual location, name, and connection resources in time. Incomplete date ranges are acceptable when data available to the editor and contributor are insufficient. It is preferable to get a correct, if incomplete, record published sooner rather than deferring publication for an extended period of time pending the acquisition of additional information.

About References

Pleiades uses references to external books, articles, websites, datasets, and other information resources in order to contextualize the information we present, to provide access to evidence or argument, and to attribute ideas and conclusions to their originators. References may be attached to places, names, locations, and connections as indicated in the sections below on each type of information resource in Pleiades.  Introductory and contextual comments may be found in the "References in Pleiades" section of the Citation Guide.

Structure of References

Every reference in Pleiades has several fields:

Citation type
Keyword/phrase drawn from a controlled vocabulary indicating the purpose and function of the reference in its context of use on Pleiades. A separate document explains the individual citation types. Each major section below discusses the appropriate application of citation types in the context of a particular class of information resource. 
Short Title
An abbreviated title or acronym by which the work cited is known or by which it can be called. Acronyms already in common or regular specialist use in scholarly literature may be used, where appropriate. Otherwise, when the first author and date of publication is known, a "last name + year" formulation is preferred (e.g., Pickard 2017). In cases where neither of these approaches are applicable, the regular title of the work may be entered, omitting text appearing after a colon, if any.
Citation Detail
Additional citation scope information needed to locate the relevant portion of the work (if appropriate). For example, if citing only a short page range in a monograph or a particular inscription in a corpus volume, this field might contain text like "pages 37-38" or "number 42". If an entire journal article is being cited as a work, the full page range of the article may be included here.  The editors prefer that the type of scope (e.g., "pages" or "number") be written out fully in English, rather than abbreviated. The exception to this rule affects primary sources for which a canonical citation scheme is in regular use (e.g., "3:17" rather than "chapter 3, verse 17" when citing a Biblical work).
Formatted Citation
A complete, human-readable formatted citation for the work and the detailed citation scope. The content of this field is analogous to a traditional, full bibliographic footnote.  Any standard citation style may be used, so long as it provides clear, complete, and actionable bibliographic information. The "Fetch from Zotero" function for references uses a default style to populate this field automatically with information about the work. If "Fetch from Zotero" is used, citation detail information (if any) must be added to this field by hand.
Bibliographic URI
Optional HTTP(S) link to a structured bibliographic record for the work cited. and are preferred targets. 
Access URI
Optional HTTP(S) link to access the work itself. Links to paywalled resources (e.g., JSTOR) are acceptable provided the target serves up a landing page for unauthenticated/unauthorized visitors. Ensure that behind-the-wall forms of the link (e.g., those containing "ezproxy") are not used. This field must contain an open, web-facing URI.
Alternate URI
Optional secondary HTTP(S) link to access the work if the "access URI" fails. The Internet Archive's Wayback Machine is the preferred target here, assuming the item in question is archived. Institutional and subject-area digital repositories are also acceptable targets; however, links to papers posted to or other for-profit sites are not acceptable. 
Other Identifier
Optional field for other identifiers (e.g., DOIs, ISBNs), which must be separated by semicolons.

Guidelines for Place Resources

The following editorial conventions are employed in the titling of place resources in Pleiades:

Structure of Place Resources


Place Titles

Titles for place resources in Pleiades are always rendered in Roman characters. Romanization (transliteration) practice is laid out in the Name Romanization Guide.

When appropriate, titles can contain one or more toponyms.

  • For every toponym used in the “title” field of the place resource, a corresponding name resource must be attached to the place resource before submitting for review.

  • When there is an ancient toponym that can be assigned to a place with full confidence, and that toponym is well-known or appears widely in literature, that toponym should be used in the title of the place resource. Minor variants (e.g., “Aphrodeisias” for “Aphrodisias”) registered as names should not be considered for place titles.

  • When no ancient toponym can be assigned to the place with full confidence, the modern toponym conventionally associated with the place by historians and archaeologists should be used in the title of the corresponding place resource (e.g. “Franchthi Cave”). Where common, the use of English spellings for modern toponyms in place resource titles are preferred (e.g., “Munich” rather than “München”), but otherwise the most common or native modern language name should be used. When the commonly-used name is actually the placename of a nearby community (e.g., Piazza Armerina) or of a higher-order administrative division (e.g., the Comblessac commune in France), the title should be extended to make clear the relationship, e.g.: "Gallo-roman villa in Comblessac" or "Birdoswald Roman Fort."

  • If the place is a natural feature and is consistently referred to by a compound name in historical sources (e.g. “Olympus Mons”), use the Romanized version of the name as it appears in those sources. In all other cases, Latin feature-type strings and abbreviations (“M.”, “fl.”, “ins.”) are now deprecated, and English terms should be used instead: so “Tiber River” instead of “Tiber fl.”, “Chios island” instead of “Chios ins.”, “Mount Ida” instead of “Ida M.”.

  • When multiple toponyms are included in a place title, they must be separated with a slash (“/”) character. When many toponyms are attested for a single place, Pleiades users and editors should exercise their best judgment as to how many to include in the title, and in what order. The editors will only in exceptional circumstances approve titles containing more than two toponyms. Preference should be given to the most common toponyms, and those representing distinct linguistic and cultural threads in the history of the place. Toponyms used regularly in modern scholarship and general literature are preferred over more obscure ones.

When there is neither an ancient nor a modern toponym firmly associated with the place, a descriptive title using the type of place should be used. These titles may incorporate short statements of spatial proximity. E.g., “Roman Bridge near Twice Brewed” or “Gladiatorial School at Carnuntum”.

Summaries for Places

Each place in Pleiades should have a concise summary that helps to identify and situate the place. The summary text should identify primary, salient features of the place. For physical geographic features, this might include indicating the modern place or feature to which the ancient place corresponds. For settlements or other anthropic features, the summary should help to identify the nature and importance of the place. Longer, discursive description or discussion of the place should be reserved for the ‘details’ field. For ancient places that either require or would benefit from disambiguation, the summary field can help to provide clarity, for example differentiating the Pandosia of Bruttium from the Pandosia of Lucania.

References for Places

Secondary works: If at all possible, a place resource should have at least one reference to a secondary work providing information, argument, etc. for the place in question. Do not add references that have not been consulted by the creator, contributor, or editor in preparation of the resource. Two citation types are available for references to works that have been consulted or that are being recommended:

  • "See further" is used for a work, or a segment of a work (indicated with the "citation detail" field) that is primarily concerned with this particular place. For example, a final excavation report on a particular rural villa would merit "see further" when cited in the context of the Pleiades place resource describing that villa.
  • "See also" is used for a work, or segment of a work, that is primarily concerned with another topic, but that is relevant to the place. For example, the Wikipedia article for Cordoba is principally concerned with the modern city, but it contains a substantive subsection devoted to the "prehistory, antiquity and Roman foundation of the city". The Pleiades reference to such an article should use the "See Also" citation type.

Gazetteers and atlases: When an entry in another spatio-temporal resource like a gazetteer, atlas, or map addresses the same place as the Pleiades resource -- and when that external entry assigns a stable identifier to the place or to that entry -- the Pleiades reference should make use of the "Related" citation type.

Primary sources: When a primary source describes an ancient place and the creator, contributor, or editor of the corresponding Pleiades resource thinks a reference to it would be helpful to users, that primary source may be cited in addition to secondary sources. In such cases, the "Evidence" citation type must be used for the primary source reference. Note that such primary source citations must not supersede appropriate citation of primary source witnesses in subordinate "name" resources. They need not replicate primary source citations made in subordinate name, location, and connection resources.

The "data source" and "citation" types must not be used on references in place resources.

Details for Places

The "details" field in a Pleiades place resource provides for extended discussion, clarification, description, and background. The field is "rich text," so links, images, headings, and other formatting may be included. Descriptive information too long to fit in the "summary" should be put in the details field. Short essays concerning the history, archaeology, etc. of the place may also be included here. 

Connections between Places

A place may have any number of relationships with another place. These may be topographical (physical part of), governmental (administrative part of), spatial (near), etc. A separate "connection" resource is provided for recording information about such relationships. See further the guidance on connection resources, below.

Place retraction


Guidelines for Location Resources

In Pleiades, locations provide a link between a conceptual place and specific geographic and temporal coordinates. They must be typed using the Location Category vocabulary. Regardless of type, each location must have a spatial geometry (point, polyline, or polygon) and at least one associated chronological period. Each type should be titled in a particular manner as specified in the following subsections. Every location must also have a positional accuracy statement.

When the OpenStreetMap (OSM) dataset contains accurate and complete spatial geometry for the extant remains of an ancient feature, Pleiades contributors should import that data from OSM, rather than creating a new location resource manually on the basis of publicly available aerial imagery, previously published maps, or other third party sources. If the extant features of interest are not currently mapped in OSM -- or if they are incorrect or inadequate therein -- please read "When you should contribute your data to OpenStreetMap before Pleiades" before proceeding further. If you are unfamiliar with OSM, the Wikipedia article about it does a good job of introducing the project and its history.

Representative Locations

A “representative location” in Pleiades comprises a representative point, polyline, or polygon for the associated place as a whole, including approximations and estimates of centerpoint, extent, perimeter, or area. Note that geometry associated with the modern extent of an archaeological area or preserve should be treated as an Associated Modern Location (q.v.).

When the place resource corresponds to a site or complex of features or monuments, the geometries of those individual monuments must not be used as locations for the place; rather, an individual place resource must be created for each subordinate, discrete monument or building one wishes to map and an appropriate location resource created for each. Use “connections” from the subordinate places to indicate the relationship with the parent place. In cases such as this, there is no need to create a representative location for the parent place: Pleiades will automatically calculate a representative point for it using the centroid of the locations associated with each subordinate place. A new place resource may be submitted and published with only a subset of its possible locations defined. Rapid publication of accurate but incomplete resources is always to be preferred over extended delay.

Titles for Representative Locations

The title of a Representative Location must reflect the source of the coordinates. When the coordinates are copied from an external data source (like OpenStreetMap or a digitized map), begin the location titles with an abbreviation of the title of the external source and append the word “location”. For example:

  • “DARMC location”

  • “OSM location”

  • “DARE location”

  • “TAVO location”

When coordinates are obtained through imagery analysis or data collection in the field, follow a similar pattern for the title (e.g., “GPS location” or “Imagery location”).

Wherever possible, add a short string to the title to provide clarity regarding the relevance of the coordinates provided. Repetition of information in the associated place title is acceptable, but qualifications longer than 3 or 4 words should be relegated to the “summary” field.

Here are some examples of titles for representative locations:

  • BAtlas Location of the Athenian Agora

  • GPS Location of the extant spans of the aqueduct bridge

  • OSM location for Centerpoint of the Athenian Agora

  • GPS location of the North end of aqueduct

Summaries for Representative Locations

The summary for a Representative Location must indicate that the location is “representative”, and then go on to summarize the nature and process of collection for the coordinates and other information contained in the location resource. The names of data sources, when abbreviated in the title, should be spelled out in the summary for the benefit of new users and third-party consumers of exported data. When published plans, maps, or descriptions have been consulted as part of the process of identifying a feature in OpenStreetMap, Google Earth, or another digital dataset, these should be mentioned in the summary or details field and cited appropriately as references. Some summary examples:

  • “Representative point derived from an OpenStreetMap node”

  • “Polygon representing the perimeter of the archaeological site, derived from an OpenStreetMap way”

  • “Representative point derived from GeoNames. Dates after the Barrington Atlas.”

Dates for Representative Locations

The date range for a representative location should include all periods for which evidence of significant human activity can be associated with the site, beginning with the date of the feature’s creation and continuing to its abandonment. This will not necessarily be clear-cut, since some buildings were active parts of the landscape even after they had fallen into ruin, and others were transformed but remained continually in use into the modern period (for example, the Hephaisteion in Athens, which was used as a church until the 20th century). When in doubt, provide at a minimum the period during which the feature was created (if known) or during which it was used for its primary purpose. Archaeological evidence is the preferred source of such dates; however, literary and documentary testimony of existence or activity may also serve (and sometimes may be the only option). Care should be exercised whenever possible to avoid asserting activity in a period based solely on an antiquarian collection of placenames (e.g., the Suda or Stephanus of Byzantium).

References for Representative Locations

When geometry (coordinates) has been copied from an external data source, whether digital or in print, the original source of the data must be cited. The citation type to use is “Cite As Data Source”.

"See further" and "see also" should be used for all other citations of secondary literature, following the guidance set out for references in place resources, even when these are used to help determine the location with reference also to (e.g.) Google Earth imagery.

When inferring date, identification, or spatial position from an ancient literary or documentary source, use the “Cite as Evidence” citation type. Primary sources should not otherwise be cited in Pleiades location resources.

Retraction rules for Representative locations

When a new location is added to place and is demonstrably more accurate than a previously published location, the previously published location should be retracted by the editor who is publishing the new location. When the newly retracted location proves to have been derived from another gazetteer, atlas, map, or online data source (i.e., it is a DARMC location or has a reference of citation type "data source"), then a new reference should be created on the parent place, using the "related" citation type and citing the originally imported resource.

Associated Modern Locations

An “associated modern location” comprises a point, line, or polygon for a modern settlement or physical feature associated with an ancient place. When the precise location of an ancient cultural site is unknown (or data is presently unavailable), a nearby or associated modern settlement may be used (especially when that settlement’s name is often used in the scholarly literature as a proxy title for the ancient site). Similarly, in the absence of solid geophysical and geoarchaeological data for the location of an ancient physical feature, an Associated Modern Location can be used.

NB: Associated Modern Locations should not be used to link Pleiades content to external, presentist gazetteers like GeoNames. A new citation type (“Related To”) has been added to references and should be used at the place level for this purpose.

Titles of Associated Modern Locations

The title of an Associated Modern Location must follow the titling guidance laid out above for Representative Locations, with the following additions. The title for a cultural location should have a string like “of modern [Romanized modern placename]” appended. The title of a physical feature should have a string like “of [Romanized modern placename]” appended.

Summaries of Associated Modern Locations

The summary for an Associated Modern Location must indicate that it is an associated modern location, and also summarize the nature and process of collection for the coordinates and other information contained in the location resource in the same manner as for Representative Locations. Some examples:

  • “Polygonal geometry representing the perimeter of the modern commune of Crecy, which is thought to be associated with the ancient site of Cremium. Geometry derived from an OpenStreetMap way;”
  • “Point marking the modern summit of Gebel Musa, which is identified with the ancient Tiberius Mons. Point derived from an OpenStreetMap way.”

Dates for Associated Modern Locations

For cultural features, the date range for a location of this type should begin with the earliest phase of the modern settlement presently known or available to the contributors and editors and continue to the present. For natural features (rivers, lakes, mountains, coastlines, etc.), even when there is evidence that those features were places in antiquity, the date range should be “modern”. There have been substantial geological changes between antiquity and the present, and the location of a river or lake today is often different from its location in antiquity.

References for Associated Modern Locations

Follow the guidance provided above in the section on “References for Representative Locations”.

Retraction Rules for Associated Modern Locations


About Positional Accuracy in Locations

All Pleiades location resources must include an appropriate "Positional Accuracy Assessment" document. The editors have made available a number of standard/generic such documents, appropriate for most locations.

Preferred Digital Resources:

Imagery Assessment:

Print Atlases, Maps, and Gazetteers:

Other Digital Resources:

The Editors welcome discussion by users -- preferably on the Pleiades Community List -- concerning available accuracy assessments, the horizontal accuracy bounds they suggest, and perceived needs for additional such documents.

Note that a number of other positional accuracy assessment documents exist, reflecting the characteristics of particular datasets that have previously been imported into Pleiades. These should not be used for coordinate data entered in Pleiades going forward without prior approval from the Editors.

Guidelines for Name Resources

See also our point-and-click tutorial: Add a new name resource.

A single place can have many names over time, or may be called different names by different groups: Ephesus, for example, has also been known as Arsinoe, Afsis, and Aya Soluk, among others. In Pleiades, each such name for a place is recorded using a separate name resource. No distinction is made between “primary” and “alternate” toponyms, nor between major and minor variants of a toponym. Each varying string of characters used as a toponym in a writing system is given a separate Pleiades name resource. Both geographic names (Ephesus) and ethnic names (Ephesians) may be added.

Structure of Name Resources


Name Titles

Pleiades automatically uses the first Romanized form of the name as the title for the resource. Unlike the edit forms for place and location, no separate “title” field appears on the name edit form.

Romanized forms of name

At least one Romanized form of a toponym must be entered for each name. Additional Romanization forms (e.g., those conforming to another of several possible Romanization schemes) may be added to the “Romanized Name” field. Separate these with commas. If the attested form of the name (see below) is in a non-Roman writing system, please ensure that the first Romanized form employs an unaccented transliteration scheme. For example: Cherson, Kherson. See the Name Romanization Guide for technical and language-specific details.

Certainty of names

In the "level of uncertainty" field, if you are completely sure this name is to be connected with the geographic location(s) already associated with the place resource, then choose "certain." "Less certain" and "uncertain" are appropriate values if there is some debate or question surrounding the association of an ancient name with a particular location. If you use "less certain" or "uncertain", you should add an explanation in the "summary" field and cite any relevant sources using the "References" tab. Values available for this field are drawn from the Association Certainty vocabulary.

Attested form of name

With the exception of data imported from legacy sources by the editors, name resources added to Pleiades must include the attested form of the toponym in its original language and script. The “attested name” field is provided for this purpose. Values entered in this field must be encoded using UTF-8 character encoding and conforming to the Canonical Composition Normalization Form.

In languages that employ inflected forms for nouns, a name occurring only in oblique case should be normalized to its nominative form if this can be done confidently. The oblique form may be noted in the "Details" field, along with accompanying discussion as appropriate.

When traditional scholarly practice further normalizes or regularizes text for presentation in an edition (e.g., Classical Greek where diacriticals for breathing and accentuation are regularly added even if absent or anachronistic), such practices may be followed in Pleiades. Conversely, a Pleiades contributor may depart from such conventions when it is appropriate for clarity or integrity of the information (e.g., when placing an accent would be problematic).

When all available witnesses can only provide a fragmentary record of a placename, the missing section(s) of the name must be set off by "square brackets" (i.e., "[" and "]"). If the missing text can be restored with confidence, it should be placed between the brackets. If restoration is not possible, or there is scholarly controversy, then two or three hyphens should be placed between the brackets and any possible supplements presented and discussed in the "Details" field. Note also: Name Completeness.

Language and writing system of name

Standard codes for a variety of language and writing system combinations are provided on the edit form for name resources, and the appropriate value must be selected before a name can be published. If the language or script of the attested name is not present in the pull-down menu, please email with a request for its addition.

References for names

Unlike a location, for which there may only be archaeological evidence, a name must be attested in, or able to be inferred from, a textual source; therefore a record for a name must always have at least one reference (of type “evidence”) to a textual source in which it is attested. When the name is ancient, attestations should also be ancient; when the name is modern, any widely used or authoritative work may be cited as evidence. In most cases, modern scholarship should only be cited as evidence for an ancient name if it involves the primary publication of ancient written sources like coins or inscriptions. Modern scholarship may also be cited (using the “see further” or "see also" citation type) if it deals directly with linguistic reconstruction of the name from corrupt or later witnesses or if it addresses the identification of the ancient name with the site. Other citation types should not be used on Pleiades name resources. 

Dates for names

A name must also always be associated with one or more temporal attestations; at a minimum, it should be associated with the period during which the primary textual source that mentions it was created (or, if the textual source is clearly referring to an earlier time – “in the time of Peisistratus, it was called X” – to the period with which the textual source associates it).

Retraction rules for names


Guidelines for Connection Resources

Structure of Connection Resources

See also our point-and-click tutorial: Add a new connection between two places.  


Connection Titles

NB: These title guidelines cannot be implemented until Issue #300 is resolved (connection titles are currently auto-assigned). 

Connection titles should combine a title or name of the target place resource with the nature or import of the connection type in a short, prepositional or adjectival phrase like:

  • "On the island of Sicily"
  • "South of Athens"
  • "In the Roman province of Moesia Inferior"
  • "On the banks of the Derventio river"
  • "United through sunoikisis with Kos"

Connection Target: "Makes a connection with..."


Connection Type

A "connection type" is required, and it must be selected from the "Relationship Types" vocabulary list curated by the editors. Proposals for the addition of new terms may be emailed to or raised for discussion on the Pleiades Community List.

Association Certainty for Connections


Temporal Attestations for Connections


References for Connections

With the exception of straightforward physical relationships evident from location, connections must cite a combination of primary and secondary literature that supports the asserted relationship between the two relevant place resources. For example an appropriate primary source reference (citation type: "evidence") might assert that a particular Chinese settlement was in a particular administrative district at a given date or might document the presence of a Roman provincial governor hearing cases there in a settlement. Appropriate secondary references (using the "see further" or "see also" citation types) should be introduced when they provide analysis or argument essential to understanding the asserted connection. The other citation types are not appropriate in this context.