Ptolemy and the Greek Influence
The Greeks, in the 300s BC, were aware that the earth was a sphere.
Claudius Ptolemy (c.100-168) was the most influential Greek astronomer and geographer of his time. Born in Egypt, he compiled information on other lands and the earth in general. He wrote many important books about mapping.
Ptolemy did a lot of research at the great library of Alexandria in Egypt where documents from writers, geographers and mathematicians who had come before him were stored.
Though extremely useful, many of his maps were inaccurate and distorted as there was not enough information at the time, particularly about places outside the Roman Empire.
Ptolemy's Map Creations
Ptolemy's work was lost to the West until the Renaissance when his writings, rather than his maps, survived. People who constructed maps in the fifteenth and sixteenth centuries recreated the maps of Ptolemy by following the notes and writings in his books. Look at the map below from 1503 which was based on Ptolemy's writings
During the middle ages, or medieval period, it was traditional to draw maps with a religious perspective - Jerusalem was often shown as the centre of the world. As the Vikings explored in the Atlantic, discovering Iceland, Greenland and America, some of their discoveries were incorporated.