This is a study of a ledger written by Andrea di Gherardo Casoli between the years 1387 and 1412. Andrea was a lawyer in the Tuscan city of Arezzo, shortly after the city lost its sovereignty to the expanding Florentine state. While Andrea associated his identity with his legal practice, he engaged in many other, diverse enterprises, such as wine making, livestock commerce, and agricultural management. This thesis systematically examines each major facet of Andrea's life, with a detailed assessment of his involvement in rural commerce. Andrea's actions revolved around a central theme of maintaining and expanding the fortunes, both financial and social, of the Casoli family.