Hipparchus. 1. A native of Niceea in Bithynia, flouristied from 160 to 125 B.C. He was the first to apply strict mathematical methods lo astronomy, and he probably made the catalogue of 1,080 stars preserved by Ptolemy. Only one of his works is extant, viz. A Commentary on the Phenomena of Aratus and Eudoxus.
2. Son of Pisistratus, Tyrant of Afhens, who in herited supreme power jointly with his brother Hippias in 527 B.C. Though he seems to have been an enlightened ruler, and a patron of art and letters, he was assassinated in 514 by Harmodius and Aristogeiton (q.v.). His brother retained authority till 511, but displayed in these latter years a cruel and suspicious temper. of being expelled, he betook himself to the court of Darius, and is said to have acted as guide to the Persians in their invasion of Greece, perishing at the battle of Marathon in 490.