Imagery location of The Great Altar at Pergamon

The Great Altar of Zeus, constructed during the first half of the 2nd century BC, is a monumental altar on a high platform, with two projecting wings; its Hellenistic Baroque sculptural program includes a high-relief Gigantomachy around the outside of the building and an interior frieze depicting the story of the mythical hero Telephos.

The remains of the Great Altar lay perched one of the terraces in the ancient city of Pergamon. First excavated in 1878 by Carl Humann and Alexander Conze, the remnants of the monument were brought to Germany, where they were reconstructed at the Berlin Royal Museum. The reconstructed altar now stands in the Pergamonmuseum in Berlin.

The Great Altar is an exaggerated version of traditional Greek stepped altars. It consists of a broad rectangular platform, atop which is a pi-shaped colonnade enclosing a sacrificial area. The wings of the colonnade stand on projecting piers on either side of the wide staircase that leads up to the sacrificial area. Along these piers and over the outside face of the platform is a detailed frieze under the platform depicting a Gigantomachy of over 200 gods and giants doing battle. Distinguished by the artistic depiction of movement and extreme emotion, the relief sculpture is a noted example of the Hellenistic Baroque style. The depictions of the adventures of Telephos in the interior frieze glorify a hero who the Pergamenes considered to be the mythical founder of their city.

The occasion of the construction of the Great Altar is debated. It may have been commissioned by either Attalos II or Eumenes II to commemorate a military victory; if it was the latter, it was probably a symbol of victory over the Gauls in 167 BC. In either case, it is widely agreed that the altar was actually built during the reign of Eumenes II from 197-159 BC, and certainly before the death of the last Attalid king in 133 BC.