Leonardo of Pisa

Leonardo Bonacci, known as Fibonacci, was an Italian mathematician from Pisa who lived roughly from 1170 to the 1240s and has been called the most talented Western mathematician of the Middle Ages. His 1202 book Liber Abaci demonstrated the practical advantages of the Hindu-Arabic numeral system over Roman numerals for commerce and accounting, and was central to popularizing that system across Europe. In the same book he introduced Europe to the sequence of numbers now called the Fibonacci sequence, presented as a problem about the growth of a rabbit population.