Hipparchus was a Greek astronomer, geographer, and mathematician. He is considered the founder of trigonometry, but is most famous for his incidental discovery of the precession of the equinoxes. Hipparchus was born in Nicaea, Bithynia, and probably died on the island of Rhodes, Greece. He is known to have been a working astronomer between 162 and 127 BC.

Nicaea, also known as Nikaia, was an ancient Greek city in the north-western Anatolian region of Bithynia that is primarily known as the site of the First and Second Councils of Nicaea, the Nicene Creed, and as the capital city of the Empire of Nicaea following the Fourth Crusade in 1204, until the recapture of Constantinople by the Byzantines in 1261. Nicaea was also the capital of the Ottomans from 1331 to 1335.