The Pergamon Altar () was a monumental construction built during the reign of the Ancient Greek King Eumenes II in the first half of the 2nd century BC on one of the terraces of the acropolis of Pergamon in Asia Minor. The structure was 35.64 metres (116' 31/32") wide and 33.4 metres (109' 6 5/8") deep; the front stairway alone was almost 20 metres (65' 11/16") wide. The base was decorated with a frieze in high relief showing the battle between the Giants and the Olympian gods known as the Gigantomachy. There was a second, smaller and less well-preserved high relief frieze on the inner court walls which surrounded the actual fire altar on the upper level of the structure at the top of the stairs. In a set of consecutive scenes, it depicts events from the life of Telephus, legendary founder of the city of Pergamon and son of the hero Heracles and Auge, one of Tegean king Aleus's daughters. In 1878, the German engineer Carl Humann started official excavations on the acropolis of Pergamon, an effort that lasted until 1886. The relief panels from the Pergamon Altar were subsequently transferred to Berlin, where they were placed on display in the Pergamon Museum. The altar in antiquity Historical background The Pergamene kingdom founded by Philetaerus at the beginning of the 3rd century BC was initially part of the Hellenistic Seleucid empire. Attalus I, successor and nephew of Eumenes I, was the first to achieve full independence for the territory and proclaimed himself king after his victory over the Celtic Galatians in 228 BC. This victory over the Galatians, a threat to the Pergamene kingdom, secured his power, which he then attempted to consolidate. With conquests in Asia Minor at the expense of the weakened Seleucids he could briefly increase the size of his kingdom. A Seleucid counteroffensive under Antiochos III reached the gates of Pergamon but could not put an end to Pergamene independence. Since the Seleucids were becoming stronger in the east, Attalus turned his attention westward to Greece and was able to occupy almost all of Euboea. His son, Eumenes II, further limited the influence of the Galatians and ruled alongside his brother Attalus II, who succeeded him. In 188 BC, Eumenes II was able to create the Treaty of Apamea as an ally of Rome, thus reducing the influence of the Seleucids in Asia Minor. The