Megăcles in Harpers Dictionary of Classical Antiquities
A name borne by several of the Athenian family of the Alcmaeonidae. The most important of these was the Megacles who put to death Cylon and his adherents after they had taken refuge at the altar of Athené, B.C. 612. (See Cylon.)
Son of Alcmaeon , son-inlaw of Clisthenes, leader of the Alcmaeonidae in the time of Solon. At first he was opposed to Pisistratus, and expelled him from Athens; but afterwards he became reconciled to him, gave him his daughter Coesyra in marriage, and assisted in his restoration to Athens. Pisistratus not having treated his wife in a proper manner, Megacles resented the affront, and again drove the former out of Athens; with the aid of large sums from the Thebans and other States, Pisistratus again raised an army, defeated his opponents, and drove Megacles and the partisans of the Alcmaeonidae into exile.
A Syracusan, brother of Dion, and brother-in-law of the elder Dionysius. He accompanied Dion in his flight from Syracuse, B.C. 358, and afterwards returned with him to Sicily.
Megacles in Wikipedia
Megacles (Μεγακλῆς) was the name of several notable men of ancient Athens:
1. Megacles was possibly a legendary Archon of Athens from 922 BC to 892 BC.
2. Megacles was a member of the Alcmaeonidae family, and the archon eponymous in 632 BC when Cylon made his unsuccessful attempt to take over Athens. Megacles was convicted of killing Cylon (who had taken refuge on the Acropolis as a suppliant of Athena) and was exiled from the city, along with all the other members of his genos, the Alcmaeonidae. The Alcmaeonidae inherited a miasma ("stain") that lasted for generations among Megacles' descendants.
3. Megacles, the grandson of the above 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 claims 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. This event is subject to debate as to whether Herodotus has interpreted this episode correctly. However, Megacles turned against Pisistratus when Pisistratus refused to have children with Megacles' daughter, which brought an end to the second tyranny.
This Megacles later competed circa 560 BC or later with Hippocleides, a former archon of Athens, to marry Agarista, the daughter of Cleisthenes of Sicyon. They had two sons; the elder Hippocrates was father of another Megacles (ostracized 486 BC) and a daughter Agariste was mother of Pericles and Ariphron (himself the father of Hippocrates of Athens who died 424 BC). The younger son Cleisthenes was allegedly father of Deinomache (or Dinomache), mother of Alcibiades (d. 404 BC). Thus, Megacles the elder was great-grandfather of Pericles and Alcibiades.
4. Megacles, grandson of the above, son of Hippocrates, and nephew of Cleisthenes is sometimes described as the father of Deinomache and thus the maternal grandfather of Alcibiades. Other sources, notably William Smith, insist that his uncle Cleisthenes was the grandfather of Alcibiades.
In 490 BC, in the aftermath of the Battle of Marathon, a shield-signal was raised on Mount Pentelicon above Marathon supposedly to signal the Persians to sail around Cape Sounion and attack the unguarded city of Athens. Herodotus reports that the Alcmaeonidae were widely believed to have been behind this act of treachery. With Megacles being the leading figure of the Alcmaeonid clan at the time, a lingering suspicion of medism hung over him.
In 486 BC Megacles was ostracised. Numerous ostraca have been found with comments on them making reference to his ostentatious wealth and love of luxury.
He was honored by Pindar as exiled winner in the chariot race of Pythian Games 486 BC.