Papyrus Rhind
The earliest mathematical texts available are from Mesopotamia and Egypt – "Plimpton 322" (Babylonian c. 2000 – 1900 BC), the "Rhind Mathematical Papyrus" (Egyptian c. 1800 BC) and the "Moscow Mathematical Papyrus" (Egyptian c. 1890 BC). All of these texts mention the so-called Pythagorean triples, so, by inference, the Pythagorean theorem seems to be the most ancient and widespread mathematical development after basic arithmetic and geometry.