This research discusses The Treasure of the City of Ladies, a manuscript written by Christine de Pizan in France during the early 15th century to give guidance on account keeping and budgeting. Christine de Pizan was born in Italy but raised in the French royal court. Her manuscript gives the keeping of accounts and budget management a religious imperative. She describes them as functions where the three divine virtues of reason, rectitude, and justice are applied. Christine de Pizan describes how demonstrating these virtues through the proper keeping of accounts and budgets is a way to demonstrate love of God. Although historical accounting records show how accounting was done, this manuscript explains why it was done. In giving a rationale for single-entry bookkeeping and budgeting, the manuscript provides a source that prevents present-mindedness when attempting to undertake contemporary analyses of accounting records from this historical period.