(1170 to 1250)
Fibonacci or Leonard of Pisa, played an important role in reviving ancient mathematics and made significant contributions of his own. Liber abaci introduced the Hindu-Arabic place-valued decimal system and the use of Arabic numerals into Europe.
Liber abaci, published in 1202 after his return to Italy, is based on bits of arithmetic and algebra that Fibonacci had accumulated during his travels.
In Liber abaci he approximates a root of a cubic equation; x3 +2x2 +10x = 20 obtaining an answer which in decimal notation is correct to 9 places. As Fibonacci had travelled in Islamic lands, he probably used an Arabic method of successive approximations.