Amatus of Montecassino (), (11th century) was a Benedictine monk of the Abbey of Montecassino who is best known for his historical chronicles of his era. His "History of the Normans" (which has survived only in its medieval French translation, "L'Ystoire de li Normant"), is one of three principle primary sources for the Norman Conquest of southern Italy--the other two being the histories of William of Apulia and Geoffrey Malaterra. Amatus describes the Normans from the perspective of his abbey, one of the most important religious and cultural centers in Italy at the time. His history is the earliest extant account of the Norman sieges of Bari and Salerno, their conquest of Sicily, and the careers of both Robert Guiscard and Richard Drengot, as well as the Gregorian Reforms seen from the papal point of view.