This paper investigates why, in 1494, the Franciscan friar and teacher of mathematics, Luca Pacioli, published an instructional treatise describing the system of double entry bookkeeping. In doing so, it also explores the rhetoric and foundations of double entry through the lens of Pacioli's treatise. Recent findings on Pacioli's life and works, his writings, and the medieval accounting archives are combined to identify how he was inspired by his faith and his humanist beliefs to give all merchants access to the practical mathematics and the bookkeeping they required. The paper finds that Pacioli's teaching method was inspired by Euclid, his Franciscan education, and his humanist beliefs, and that Pacioli reveals a simplicity in the then-unrecognized axiomatic foundation of double entry that has been largely overlooked. The findings represent a paradigm shift in how we perceive Pacioli, his treatise, and double entry.

The emergence of double entry bookkeeping marked the shift in bookkeeping from a mechanical task to a skilled craft, and represented the beginnings of the accounting profession. This study seeks to identify what caused this significant change in bookkeeping practice. I do so by adopting a new accounting history perspective to investigate the circumstances surrounding the emergence of double entry in early 13th century Italy. Contrary to previous findings, this paper concludes that the most likely form of enterprise where bookkeeping of this form emerged is a bank, most likely in Florence. Accountability of the local bankers in Florence to the Bankers Guild provided a unique external impetus to generate a new form of bookkeeping. This new bookkeeping format provided a clear and unambiguous picture of the accounts of all debtors and creditors, along with the means to check that the entries between them were complete and accurate.