The Alcmaeonids (alk-MEE-oh-nids) were a very rich family who lived in Athens in the Archaic and Classical periods. "Alcmaeonids" means the descendants of Alcmaeon. The Athenians thought that all the Alcmaeonids were under a curse.
The first time we hear about the Alcmaeonids, they're fighting against a man called Cylon (SI-lonn) who wanted to become tyrant of Athens, in 631 BC. There was a big fight between Cylon and the other rich men of Athens, and finally Cylon gave up and surrendered. Cylon came out under truce, giving up, but the Alcmaeonids stabbed him to death anyway. Because they had killed someone under truce, the Athenians thought they and all their descendants were cursed. They were all banished from Athens.
The curse didn't keep the Alcmaeonids from continuing to be a powerful and very wealthy family. In 548 BC, when a terrible earthquake knocked down the temple of Apollo at Delphi, the Alcmaeonids paid to have it rebuilt, bigger and better than ever. This got the oracle at Delphi on their side.
Pericles (from a later carving in the Vatican)
When Pisistratus' son Hippias was tyrant of Athens, he was so unpopular that one of the Alcmaeonids, Cleisthenes, saw a chance to get back into power in Athens. The Delphic oracle got the Spartans to help the Alcmaeonids throw Hippias out in 510 BC. Cleisthenes went on to start the Athenian democracy.
Pericles was another famous Alcmaeonid (on his mother's side). He was a general who commanded the Athenian army in the first years of the Peloponnesian War.
The last famous Alcmaeonid was Alcibiades (he was an Alcmaeonid on his mother's side), who betrayed Athens and helped make Athens lose the Peloponnesian War in 404 BC.
To find out more about the Alcmaeonids, check out these books from Amazon.com or from your library:
The Age of Pericles, by Don Nardo (1996). For kids (I think the baby-preschool label on Amazon is wrong).
Cleisthenes: Founder of Athenian Democracy, by Sarah Parton (2002). A biography of the founder of Athenian democracy, for kids.
Pericles Of Athens And The Birth Of Democracy, by Donald Kagan (1998). Kagan is a well-known expert on classical Greece, though his views are a little more accepting of Greek racism and military aggression than I would like.
Alcibiades, by Walter M. Ellis (1989). Unfortunately this book is out of print, so you should try a library. But you never know. Maybe Routledge will reprint it.
Tides of War: A Novel of Alcibiades and the Peloponnesian War, by Steven Pressfield (2000). Not as good as Pressman's novel about Thermopylae, Gates of Hell, but still an entertaining way to find out more about Alcibiades. For older readers - a lot of violence, and some romance.