The earlier temple was called the Older Parthenon. It is also described as the Pre-Parthenon because it was an earlier attempt to build a sanctuary for Athena Parthenos on the Acropolis.
Construction began after the Greek victory at the Battle of Marathon, generally dated to around 490–488 BC. The project was built on a substantial limestone foundation that extended and leveled the southern part of the Acropolis summit. It replaced an earlier temple known as the Hekatompedon.
The Older Parthenon was still unfinished when Persian forces captured and destroyed Athens in 480 BC during the second Persian invasion of Greece. Its marble column drums and other remains were later reused in defensive walls on the Acropolis, especially the northern wall.
The present Parthenon was a later replacement, begun under the Athenian building program associated with Pericles in 447 BC. The surviving foundations and reused fragments allow archaeologists to reconstruct parts of the earlier project, even though its full design remains less certain than that of its successor.