Harmodius and Aristogeiton (Naples Museum)
But in 514 BC, two young rich men named Harmodius and Aristogeiton tried to kill Hippias and Hipparchus. They missed Hippias, but they did kill Hipparchus. Then Hippias' guards killed Harmodius and Aristogeiton.
After his brother was killed, Hippias got more and more suspicious of everyone around him, and thought everyone was plotting against him. Four years later, in 510 BC, another rich man called Cleisthenes, from the Alcmaeonid family, did succeed in getting the Spartans to help him throw Hippias out of Athens. Hippias went to live with the Persians, where he spent the rest of his life.
To find out more about Hippias and Hipparchus, check out these books from Amazon.com or from your library:
Oxford First Ancient History, by Roy Burrell and Peter Connolly (1997). Lively interviews and pictures make the ancient Mediterranean come to life. For middle schoolers.
The Oxford Illustrated History of Greece and the Hellenistic World, by John Boardman, Jasper Griffin, and Oswyn Murray (2001). For college students.
A Brief History of Ancient Greece: Politics, Society, and Culture, by Sarah Pomeroy and others (2004). This one might be a little more politically progressive than the Oxford history.