[Thales] first went to Egypt and hence introduced this study [geometry] into Greece. He discovered many propositions himself, and instructed his successors in the principles underlying many others, his method of attack being in some cases more general [i.e. more theoretical or scientific], in others more empirical [...more in the nature of simple inspection or observation].

A Commentary on the First Book of Eudlid's Elements (c. 450 AD)