The Synopsis of Histories of John Skylitzes is one of the most important sources on the history of Byzantium in the tenth and eleventh centuries. By its nature, it is a compilation of many works of other authors. In view of the fact that most of these writings have not been preserved, a great part of Skylitzes’ book is significant as a primary source. The author’s working method can be revealed by comparison with the only main source of the Synopsis that survived, the so-called Continuator of Theophanes. This article analyzes all the dated events in the work of Skylitzes, compares them with his sources, and draws conclusions about the specifics of his approach to chronology. In general, John Skylitzes, as a chronicler, stands head and shoulders above other known Byzantine authors from the tenth and eleventh century; however, his “systematic” approach to the material does not save him from errors and hyper- corrections, which makes us cautious about the chronological and other information he reports. The account of the Synopsis of Histories is of great importance for the history of Byzantine chronology.