Epistolae familiares is the title of a collection of letters of Petrarch which he edited during his lifetime. He originally called the collection Epistolarum mearum ad diversos liber ("a book of my letters to different people") but this was later shortened to the current title. Petrarch discovered the text of Cicero's letters in 1345, which gave him the idea to collect his own sets of letters. It wasn't until four or five years later however, that he actually got started. He collected his letter correspondence in two different time periods. They are referred to as Epistolae familiares and Seniles. Epistolae familiares (a.k.a. Familiar Letters) was largely collected during his stay in Provence about 1351 to 1353, however was not ultimately completed until 1359 when he was in Milan. Petrarch had this collection of letters copied onto parchment in 1359 by a certain ingeniosus homo et amicus with another complete copy done in 1364. He added letters in 1366, bringing his first collection of letters to 350. He broke these down and sorted them into 24 volumes. This first collection of letters called Epistolae familiares were actually written between the years 1325 and 1366 (the first translation into English was done by historian James Harvey Robinson in 1898 in his book The First Modern Scholar and Man of Letters). In January 1350 Petrarch wrote a lengthy letter to his dear friend ("Socrates" as Petrarch liked to call him) dedicating the collection to him. He requests his friend to keep the letters safely out of sight of the censors and critics. It has since been discovered that Socrates was the Flemish Benedictine monk and music theorist Lodewijk Heyligen whose acquaintance Petrarch had made in the circle of cardinal Giovanni Colonna in Avignon. Source: Wikipedia (en)