Fibonacci Publishes Liber Abaci, Introducing Hindu-Arabic Numerals to Europe

In 1202, Italian mathematician Leonardo of Pisa — later known as Fibonacci — published Liber Abaci, the first work to systematically introduce the Hindu-Arabic numeral system, including zero, to a European audience of merchants and tradespeople. Having learned the system in North Africa while traveling with his merchant father, Fibonacci demonstrated its practical superiority over Roman numerals for commerce, currency conversion, profit calculation, and compound interest. The book transformed European mathematics and finance. Crucially, it was not addressed to scholars but to businesspeople — which is why it succeeded where earlier academic works had not.