Leonardo Fibonacci (c.1170-c.1250), Italian mathematician. Fibonacci travelled widely throughout the Mediterranean world and studied under leading Arab mathematicians. He introduced Arab numerals and the decimal system to Europe through his Book of the Abacus (Liber Abaci, 1202). Other publications included Practica geometriae (1220) and Liber quadratorum (1225). He also discovered the Fibonacci series, a sequence of numbers in which each number is the sum of the previous two. This series is often found in nature, for example in the patterns of leaf growth. This artwork is based on a statue of Fibonacci.