Hippias of Athens (Greek: Ἱππίας ὁ Ἀθηναῖος) was born around c. 547 B.C. and was one of the sons of Peisistratus, and was the last tyrant of Athens between about 527 BC and 510 BC, when Cleomenes I of Sparta successfully invaded Athens and forced Hippias to leave Athens.
The name and family of the mother of Hippias are unknown. He succeeded Peisistratus as tyrant of Athens in 528/7 BC. His brother Hipparchus, who may have ruled jointly with him, was murdered by Harmodius and Aristogeiton (the tyrannicides) in 514 BC. Hippias executed the tyrannicides and it was said that he became a bitter and cruel ruler, executing a large number of citizens and imposing harsh taxes. Hippias's cruelty soon created unrest among his subjects. As he began losing control, he sought military support from the Persians. He managed to form an alliance by marrying his daughter, Archedice, to Aiantides, son of Hippoklos, the tyrant of Lampsakos. This relationship with Hippoklos helped facilitate Hippias' access to Darius' court at Susa.
The Alcmaeonidae family of Athens, which Peisistratus had exiled in 546 BC, was concerned about Hippias forming alliances with the Persian ruling class, and began planning an invasion to depose him. In 510 BC Cleomenes I of Sparta successfully invaded Athens and trapped Hippias on the Acropolis. They also took the Pisistratidae children hostage forcing Hippias to leave Athens in order to have them returned safely.
The Spartans later thought that a free and democratic Athens would be dangerous to Spartan power, and attempted to recall Hippias and re-establish the tyranny. Hippias had fled to Persia, and the Persians threatened to attack Athens if they did not accept Hippias back. Nevertheless, the Athenians preferred to remain democratic despite the danger from Persia.
Soon after this, the Ionian Revolt began. It was put down in 494 BC, but Darius I of Persia was intent on punishing Athens for its role in the revolt. In 490 Hippias, still in the service of the Persians, encouraged Darius to invade Greece and attack Athens; when Darius initiated the campaign, Hippias himself accompanied the Persian fleet and suggested Marathon as the place where the Persian invasion of Attica should begin. According to Herodotus, the night before the Persian fleet reached Attica, Hippias dreamed that he had sexual relations with his own mother, a dream which encouraged him greatly, since he took it as an omen that he would regain possession of his native land. But when he set foot on Greek soil, one of his teeth, which was loose due to his advanced age, fell out on to the beach. Hippias was dismayed, believing that this fulfilled the real meaning of his dream: he would only regain this bite of his native country.
Hippias had five sons, all of whom along with other Peisistratids joined the invading Persian army of Xerxes in 480 BC. Never again would the Peisistratids have influence in Athens.
Hippias was one of several Greek aristocrats who took refuge in the Achaemenid Empire following reversals at home, other famous ones being Themistocles, Demaratos, Gongylos or Alcibiades. In general, those were generously welcomed by the Achaemenid kings, and received land grants to support them, and ruled on various cities of Asia Minor.