The third Megacles, the grandson of the above eponymous archon, son of
Alcmaeon and member of the
Alcmaeonidae family, was an opponent of
Pisistratus in the 6th century BC. He drove out Pisistratus during the latter's first reign as
tyrant in 560 BC, but the two then made an alliance with each other, and Pisistratus married Megacles' daughter.
Herodotus says that they also tricked the Athenians into believing Athena herself had arrived to proclaim Pisistratus tyrant, by dressing up a woman named
Phye as the goddess, although Herodotus himself casts doubt on the truth of this story. However, Megacles turned against Pisistratus when Pisistratus refused to have children with Megacles' daughter, which brought an end to the second tyranny. This Megacles earlier had competed with
Hippocleides, a future
archon of Athens, to marry
Agarista, the daughter of
Cleisthenes of Sicyon. They had two sons. The elder was
Hippocrates, whose children were another Megacles (ostracized 486 BC) and a daughter Agariste, the mother of
Pericles and
Ariphron (himself the father of
Hippocrates of Athens who died 424 BC). The younger son was
Cleisthenes, who was allegedly the grandfather of
Deinomache (or Dinomache), mother of
Alcibiades (d. 404 BC). Thus, Megacles the elder was great-grandfather of
Pericles and the great-great-grandfather of
Alcibiades. ==Battle of Marathon==