The Geographica or Geography, is an encyclopedia of geographical knowledge, consisting of 17 'books', written in Greek in the late 1st century BC, or early 1st century AD, and attributed to Strabo, an educated citizen of the Roman Empire of Greek descent. There is a fragmentary palimpsest dating to the fifth century. The earliest manuscripts of books 1–9 date to the tenth century, with a 13th-century manuscript containing the entire text.

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.