William the Breton (c. 1165 – c. 1225), French chronicler and poet, was a contemporary and dependent of French king Philip Augustus for whom he served in diplomatic missions and for whom he wrote a Latin prose chronicle and a Latin epic poem.
Later, he became chaplain to the French king Philip Augustus, who employed him on diplomatic errands, and entrusted him with the education of his natural son, Pierre Charlot.
The former, a classicizing Latin epic poem in 12 books and composed in three redactions, gives some very interesting details about Philip Augustus and his time, including some information about military matters, and shows that William was an excellent Latin scholar.
[1] In its final form the Gesta is an epitome of the work of Rigord, who wrote a life of Philip Augustus from 1179 to 1206, and an original continuation by William himself from 1207 to 1220.
In both works William speaks in very laudatory terms of the king; but his writings are valuable because he had personal knowledge of many of the facts which he relates.