[Truncated abstract] My focus has been twofold. On the one hand I have highlighted and elucidated the events which Pachymerēs narrates, glossing with prosopographical and topological notes the people, places and things mentioned in the text, and explaining other esoteric details, such as the range of many and varied, ornate Byzantine court honorifics. On the other hand I have made a critical comparison between Pachymerēs and the other important sources for the period, Greek, Western, and Eastern, to provide explanations for differences in the various narratives, to suggest which source is the more accurate for any given event, and to fill up the narrative ‘gaps’ of Gomme .... I must stress that both by training and inclination I am an historian, not a philologist, so the commentary will be historical rather than philological. This is despite the importance Pachymerēs himself places in the clever use of language and his frequent use of allusions to and quotes from other works, Classical, Byzantine or biblical. The question of mimēsis, how much Pachymerēs is directly trying to imitate or incorporate older texts, has received limited attention, and only where Pachymerēs’ use of the earlier text is vital to the understanding of his own work. Similarly, questions of language, and the way in which Pachymerēs uses it, have not been explored except in those instances where it directly affects the historical point our author is making. Pachymerēs’ Historia is an important source for a pivotal period in Byzantine Imperial history, and many scholars have not used it as efficiently as they could due to the denseness of his prose and his “tortuous syntax” (Bartusis 1992:55) ...