Ptolemy's Geography

ancient maps · geography · history of science

First real atlas. Claudius Ptolemy wrote Geography around 150 AD in Alexandria, Egypt, and it was the first book to collect maps and descriptions of the entire known world in one place. People used it for over 1,000 years to understand where places were.

Smart system for maps. Ptolemy invented new principles for mapmaking, like ways to show the round Earth on flat paper. His methods were so clever that mapmakers copied his ideas centuries later.

Built on older work. Ptolemy didn't start from scratch. He revised and improved an earlier atlas by a geographer named Marinus of Tyre, and added information from Roman and Persian records to make it more complete.

Described the known world. The Geography was like a giant gazetteer, meaning it listed and described thousands of places, cities, and landmarks that existed in the Roman Empire and beyond. It told readers where things were located and what they were like.

Written in Greek. Even though Ptolemy lived in the Roman Empire, he wrote Geography in Greek, which was the language of educated people and science back then. Later, other people translated it into Latin and Arabic so even more people could read it.