Bruni's most notable work is "Historiarum Florentini populi libri XII" (History of the Florentine People, 12 Books), which has been called the first modern history book. While it probably was not Bruni's intention to secularize history, the three period view of history is unquestionably secular and so Bruni has been called the first modern historian. The foundation of Bruni's conception can be found with Petrarch, who distinguished the classical period from later cultural decline, or "tenebrae" (literally "darkness"). Bruni argued that Italy had revived in recent centuries and could therefore be described as entering a new age.