Short answers, pulled from the story.
Leonardo Bruni was an Italian humanist, historian and statesman active in Florence, often recognized as the most important humanist historian of the early Renaissance. He is also called the first modern historian for his three-period view of history.
Leonardo Bruni was born in Arezzo, Tuscany, around 1370, and he died in Florence on the 9th of March 1444.
Leonardo Bruni's most notable work is Historiarum Florentini populi libri XII, the History of the Florentine People in twelve books, which has been called the first modern history book. He also wrote New Cicero, a biography of the Roman statesman Cicero, and Italian-language biographies of Dante and Petrarch.
Leonardo Bruni is called the first modern historian because he was the earliest writer to divide history into three periods, Antiquity, the Middle Ages, and the Modern age. His three-period framework is unquestionably secular, even though secularizing history was probably not his intention.
Leonardo Bruni served as Chancellor of Florence, succeeding his teacher Coluccio Salutati, holding the office from 1410 to 1411 and again from 1427 until his death in 1444. He also served as apostolic secretary to four popes between 1405 and 1414.
Leonardo Bruni is buried in a wall tomb by Bernardo Rossellino in the Basilica of Santa Croce in Florence. Carlo Marsuppini succeeded him as chancellor after his death in 1444.