The geography of the sky owes a lot to Claudius Ptolemy. He was a Greek astronomer who lived and worked in Alexandria, the capital of Greek-controlled Egypt.

Almost 1900 years ago, Ptolemy published one of the most important astronomical works in history. Known as the Almagest, it contained Ptolemy’s models of the motions of the Sun, Moon, and planets, and much more. One of its most important features was a catalog of stars and constellations. It listed 48 constellations visible from the northern hemisphere, most of which had been around for thousands of years. And, thanks to Ptolemy, they’re still with us today.

The list includes Hercules, the strongman. The constellation is in the east and northeast at nightfall, and swings high overhead during the night.

“Hercules” is the Roman version of Heracles, a son of Zeus, the king of the Greek gods of Olympus. His mother was not Zeus’s wife, Hera, and Hera wasn’t happy about the situation. She tried to kill the baby, but he survived. She then set about making his life miserable.

Hera drove the adult Heracles mad, causing him to kill his family. To atone for his crimes, he was given 12 labors to complete — tests of strength, courage, and skill. Eventually, Hera relented, and allowed Heracles to join the gods on Mount Olympus — and to be placed among the stars — one of the constellations preserved by Claudius Ptolemy.

We’ll have more about Hercules tomorrow.

Script by Damond Benningfield