2. Luca Pacioli and Amatino Manucci
Around the year 1300, Amatino Manucci invented (or at least documented) double-entry bookkeeping, although fellow Italian Luca Pacioli popularised the system after publishing Summa de arithmetica, geometria. Proportioni et proportionalita in Venice nearly 200 years later. This school textbook provided the first published description of double-entry usage.
The book also detailed a method for balancing ledgers (trial balance), and Pacioli was perhaps the first to recommended independent ledger reviews to discourage fraud. Five hundred years after his publishing triumph, Pacioli was immortalised on a 1994 Italian stamp. Bravo Signor Pacioli!