Luca Pacioli

Fra Luca Bartolomeo de Pacioli (sometimes Paciolo) (1445–1514 or 1517) was an Italian mathematician and Franciscan friar, collaborator with Leonardo da Vinci, and seminal contributor to the field now known as accounting. He was also called Luca di Borgo after his birthplace, Borgo Santo Sepolcro, Tuscany. Luca Pacioli studied in Venice and Rome and became a Franciscan friar in the 1470s. He was a travelling mathematics tutor until 1497, when he accepted an invitation from Lodovico Sforza (“Il Moro”) to work in Milan.
There he collaborated with, lived with, and taught mathematics to Leonardo da Vinci. In 1499, Pacioli and Leonardo were forced to flee Milan when Louis XII of France seized the city and drove their patron out. After that, Pacioli and Leonardo frequently traveled together. Upon return to his hometown, Pacioli died of old age in 1517. Pacioli published several works on mathematics, including: Summa de arithmetica, geometria, proportioni et proportionalita (Venice 1494), a synthesis of the mathematical knowledge of his time, is also notable for including the first published description of the method of keeping accounts that Venetian merchants used during the Italian Renaissance, known as the double-entry accounting system. Although Pacioli codified rather than invented this system, he is widely regarded as the “Father of Accounting”. The system he published included most of the accounting cycle as we know it today.
He described the use of journals and ledgers, and warned that a person should not go to sleep at night until the debits equalled the credits. His ledger had accounts for assets (including receivables and inventories), liabilities, capital, income, and expenses—the account categories that are reported on an organization’s balance sheet and income statement, respectively. He demonstrated year-end closing entries and proposed that a trial balance be used to prove a balanced ledger. Also, his treatise touches on a wide range of related topics from accounting ethics to cost accounting.