Leonardo Bruni (or Leonardo Aretino) (c. 1370 – March 9, 1444) is an Italian humanist, historian and statesman, often recognized as the most important humanist historian of the early Renaissance.

He has been called the first modern historian.

He is the earliest person to write using the three-period view of history: Antiquity, Middle Ages, and Modern.

The dates Bruni uses to define the periods are not exactly what modern historians use today, but he lays the conceptual groundwork for a tripartite division of history.