The 15th-century Italian mathematician known as the “Father of Accounting” is Luca Pacioli.
Pacioli was a Franciscan friar, mathematician, teacher, and writer from Sansepolcro in Tuscany. His best-known mathematical work, Summa de arithmetica, geometria, proportioni et proportionalita, was published in Venice in 1494. It included a section called Particularis de computis et scripturis, which described the bookkeeping practices used by merchants in northern Italy.
Pacioli did not invent double-entry bookkeeping. Evidence shows that related systems were already being used by Italian merchants in the late 13th and 14th centuries. His importance lies in publishing the first detailed, widely circulated account of the method, allowing merchants and students to study and reproduce it.
The system recorded transactions through balanced debits and credits and used journals, ledgers, trial balances, and closing entries. Pacioli also worked with Leonardo da Vinci in Milan, which explains why da Vinci sometimes appears alongside him in accounts of Renaissance mathematics—but not as the father of accounting.