Amatino Manucci was the inventor of double-entry bookkeeping.
Manucci was a partner in Giovanni Farolfi & Company, a merchant partnership based in Florence

Florence

Florence is the capital city of the Italian region of Tuscany and of the province of Florence. It is the most populous city in Tuscany, with approximately 370,000 inhabitants, expanding to over 1.5 million in the metropolitan area....

. Financial records that he kept for the firm's branch in Salon, Provence, survive from 1299-1300. Although these records are incomplete, they show enough detail to be identified as double-entry bookkeeping. These details include the use of debits and credits

Debits and credits

Debit and credit are the two aspects of every financial transaction. Their use and implication is the fundamental concept in the double-entry bookkeeping system, in which every debit transaction must have a corresponding credit transaction and vice versa.Debits and credits are a system of notation...

and duality of entries. They are the oldest known extant examples of the double-entry system.