Fibonacci (/ˌfɪbəˈnɑːtʃi/; also US: /ˌfiːb-/, Italian: [fiboˈnattʃi]; c. 1170 – c. 1240–50), also known as Leonardo Bonacci, Leonardo of Pisa, or Leonardo Bigollo Pisano ('Leonardo the Traveller from Pisa'), was an Italian mathematician from the Republic of Pisa, considered to be "the most talented Western mathematician of the Middle Ages".