Luca Pacioli was an Italian mathematician and Franciscan monk in the 15th century who is considered the 'Father of Accounting' because he was the first to publish a comprehensive book on the double-entry accounting method still used today. He worked with Leonardo da Vinci and taught him mathematics. The document then lists three "Golden Rules of Accounting": debit what comes in and credit what goes out for existing accounts, credit the giver and debit the receiver for personal accounts, and credit all income and debit all expenses.