what is the function of this altar?
To avoid any direct references to contemporary military campaigns.
Pergamon Altar

The Gigantomachy frieze on the outside walls of the Pergamon altar avoids to a great extent any direct references to contemporary military campaigns 
who was themistocles and what did he do He was an Athenian politician and general who convinced the polis to increase the naval power of Athens. is his portrait found in any money belonging to that period? Yes, he was probably the first ruler ever to issue coinage with his personal portrait. any known descendants? UNANSWERABLE who succeeded as the ruler after him? Archeptolis who was he? He was a Governor of Magnesia on the Maeander in Ionia and a son of l Themistocles. where exactly is this place that he was governor of? It was an ancient Greek city in Ionia. does it still exist? UNANSWERABLE has the ancient site of this place been excavated? Yes, the first excavations were performed during 1891 and 1893. who led these excavations? Carl Humann who is this person? A German engineer, architect and archaeologist. did he excavate any other site related to an altar? Yes, the Pergamon Altar. where is this structure found? Pergamon in Asia Minor.
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Pergamon Altar [SEP] The endowment, dating and function of the altar
An important dating criterion is also the incorporation of the altar from the perspective of city planning. As the most important marble edifice of the Hellenistic residence and indeed erected in a prominent position, it was assuredly not begun only at the conclusion of numerous initiatives to upgrade the acropolis of Pergamon under Eumenes II.