(), a son of Amphiaraus and Eriphyle, and brother
of Amphilochus, Eurydice, and Demonassa. (Apollod. 3.7.2.) His
mother was induced by the necklace of Harmonia, which she received from Polyneices, to
persuade her husband Amphiaraus to take part in the expedition against Thebes. (Hom. Od. 15.247, &c.) But before Amphiaraus set out, he
enjoined his sons to kill their mother as soon as they should be grown up. (Apollod. 3.6.2; Hyg. Fab. 73.) When
the Epigoni prepared for a second expedition against Thebes, to avenge the death of their
fathers, the oracle promised them success and victory, if they chose Alcmaeon their leader. He
was at first disinclined to undertake the command, as he had not yet taken vengeance on his
mother, according to the desire of his father. But she, who had now received from Thersander,
the son of Polyneices, the peplus of Harmonia also, induced him to join the expedition.
Alcmaeon distinguished himself greatly in it, and slew Laodamus, the son of Eteocles. (Apollod. 3.7.2, &c. ; comp. Diod.
4.66.) When, after the fall of Thebes, he learnt the reason for which his mother had
urged him on to take part in the expedition, He slew her on the advice of an oracle of Apollo,
and, according to some traditions, in conjunction with his brother Amphilochus. For this deed
he became mad, and was haunted by the Erinnyes. He first came to Oicleus in Arcadia, and
thence went to Phegeus in Psophis, and being purified by the latter, he married his daughter
Arsinoe or Alphesiboea (Paus. 8.24.4), to whom he gave the
necklace and peplus of Harmonia. But the country in which he now resided was visited by
scarcity, in consequence of his being the murderer of his mother, and the oracle advised him
to go to Achelous. According to Pausanias, he left Psophis because his madness did not yet
cease. Pausanias and Thucydides (2.102; comp. Plut. De Exil. p. 602) further state, that the oracle commanded him to go to a
country which had been formed subsequent to the murder of his mother, and was therefore under
no curse. The country thus pointed out was a tract of land which had been recently formed at
the mouth of the river Achelous. Apollodorus agrees with this account, but gives a detailed
history of Alcmaeon's wanderings until he reached the mouth of Achelous, who gave him his
daughter Calirrhoe in marriage. Calirrhoe had a desire to possess the necklace and peplus of
Harmonia, and Alcmaeon, to gratify her wish, went to Psophis to get them from Phegeus, under
the pretext that he intended to dedicate them at Delphi in order to be freed from his madness.
Phegeus complied with his request, but when he heard that the treasures were fetched for
Calirrhoe, he sent his sons Pronous and Agenor (Apollod.
3.7.6) or, according to Pausanias (8.24.4), Temenus and
Axion, after him, with the command to kill him. This was done, but the sons of Alcmaeon by
Calirrhoe took bloody vengoance at the instigation of their mother. (Apollod. Paus. ll. cc.;Ov. Met. 9.407, &c.)
The story about Alcmaeon furnished rich materials for the epic and tragic poets of Greece,
and their Roman imitators. But none of these poems is now extant, and we only know from
Apollodorus (3.7.7), that Euripides, in his tragedy "
Alcmaeon," stated that after the fall of Thebes he married Manto, the daughter of Teiresias,
and that he had two children by her, Amphilochus and Tisiphone, whom he gave to Creon, king of
Corinth, to educate. The wife of Creon, jealous of the extraordinary beauty of Tisiphone,
afterwards sold her as a slave, and Alcmaeon himself bought her, without knowing that she was
his daughter. (Diod. 4.66; Paus.
7.3.1, 9.33.1.) Alcmaeon after his death was worshipped
as a hero, and at Thebes he seems to have had an altar, near the house of Pindar (Pind. P. 8.80, &c.), who calls him his neighbour and the
guardian of his property, and also seems to suggest that prophetic powers were ascribed to
him, as to his father Amphiaraus. At Psopllis his tomb was shewn, surrounded with lofty and
sacred cypresses. (Paus. 8.24.4.) At Oropus, in Attica, where
Amphiaraus and Amphilochus were worshipped, Alcmaeon enjoyed no such honours, because he was a
matricide. (Paus. 1.34.2.) He was represented in a statue at
Delphi, and on the chest of Cypselus. (10.10.2, 5.17.4.)