One is of the opinion today, that mathematics did not become a science until the Golden Age of Greece. The Egyptians were already developing, Babylonians and Phoenicians amazing mathematical knowledge, but they were only interested in practical mathematics, on the calculations, that you need for everyday life, to build, for seafaring, trade and for astronomy. They asked little or no questions about underlying theories and general rules. Only the Greeks took the giant step from practice to theory.
Our knowledge of Greek mathematics begins with Thaies of Miletus, one of the seven sages of Greece, the around 600 v. Chr. introduced the theory of geometry to Greece. The Egyptians knew though, how to measure the height of a pyramid by its shadow, but it was Thaies, who brought the underlying law into a formula and proved it, that it applies to all conceivable cases. Evidence, that a law is right under all conditions, the mathematician calls a proof.