“The Acts of Robert Guiscard ” ( lat. Gesta Roberti Wiscardi ) is one of the most important sources on the history of the Norman conquest of southern Italy, written in hexameter in Latin. The author of “Acts” is the medieval chronicler Wilhelm from Puglia , about whom practically nothing is known. Apparently, the work was created between 1096 and 1099, that is, more than 10 years after the death of the Duke of Puglia Robert Guiscard . Dedicated to Robert's son Roger . It consists of 5 books, and, despite the name, Guiscard appears in the story only from the second book. The first part of the Acts is dedicated to the early history of the Norman conquest of southern Italy. The second and third tell directly about the exploits of Guiscard in Italy. The fourth and fifth are devoted to the campaign of Guiscard on Byzantium in 1081-1085.
It is likely that the Byzantine Princess Anna Komnina , the creator of Alexiada, was familiar with the “Acts” of William. It is possible that both authors used some common third source, but this has not been clarified.