This study considers developments that led to the introduction and diffusion of double-entry bookkeeping in Tuscany in the late-thirteenth and fourteenth centuries. We examine the evolution of the four basic account books (debtors and creditors, cash, merchandise and moveable property), which, together with the capital account, established the basis of the accounting method. We reconstruct the social context of Tuscany to highlight how specific cultural factors, such as risk appetite and entrepreneurial spirit, fostered the creation of companies attentive to organisational modes of work and the valorisation of human capital. These elements, combined with an innate pragmatism of economic operators, produced innovation in the field of accounting as well. Accountants and firm managers were able to establish the double-entry bookkeeping method, which was not the result of abstract rules but rather of gradual evolution. Accounting systems can thus be considered as reflections of the society and the organisations in which they developed and spread.