Hipparchus (son of Pisistratus)
Hipparchus was one of the sons of Pisistratus. He became tyrant of Athens, along with his brother Hippias, when Pisistratus died in 528/527 BC. While Hippias was responsible for the political and economic aspects of the tyranny, Hipparchus was a patron of the arts; and it was Hipparchus who invited Simonides of Ceos to Athens.
In 514 BC Hipparchus was murdered by the Tyrannicides, Harmodius and Aristogeiton. This was apparently a personal dispute, according to Herodotus and Thucydides; Hipparchus had fallen in love with Harmodius, who was already the lover of Aristogeiton. When Harmodius rejected him, Hipparchus refused to allow Harmodius' sister to participate in a religious festival, insinuating that she was not a virgin. As a result, Harmodius and Aristogeiton assassinated him.
After the assassination, Hippias became a bitter and cruel tyrant, and was overthrown a few years later.
Not to be confused with the astronomer and mathematician Hipparchus.