Alberic's Chronicle
Written over ten years in his home monastery of Trois-Fontaines, Alberic of Trois-Fontaines' Chronicle treats world events up to the current time. The conventional dating of the Letter of Prester John to 1165 derives from Alberic, who explains that the letter was initially sent out to several European kings, but most especially to Frederick Barbarossa and Emperor Manuel. As Brewer (p. 11) explains, Alberic's Chronicle, along with scribal addition, dated to 1170, in one thirteenth-century copy of the Letter, comprise the only extant evidence regarding the original date of composition of the letter of Prester John.