Around 150 A.D., Greek (or possibly Egyptian) geographer and astronomer Claudius Ptolemaeus publishes Geographia, a seven-volume atlas of current geographic knowledge that includes the first projected, or flat, map of the Earth. Many of his representations turn out to be wrong, but Geographia breaks new ground in cartography and is considered the authoritative geography text until the Renaissance. Christopher Columbus is said to have been inspired to sail for India by a Ptolemaic map.