This volume presents, for the first time, a critical edition of a highly unusual Byzantine text: the Metaphrase – or intralingual translation – of the early 13th-century History (Chronike Diegesis) of Niketas Choniates. The original History of Choniates has always been considered a monument of Byzantine historical and rhetorical discourse. Its highly learned, Atticizing style of Greek, however, frequently made it obscure to readers, even in the Byzantine period. As a result, in the second quarter of the 14th century, probably in Constantinople, an individual or group of individuals undertook to transpose the entire work into a simpler register of Greek, closer to the everyday language of the period. Accordingly, the text as published here brings to light a major body of primary linguistic material, enabling scholars in the field to judge for themselves the nature and extent of the linguistic and stylistic enterprise represented by the Metaphrase. The introductory matter and accompanying analysis provide background information on the manuscript tradition of the Metaphrase, as well as an assessment of its linguistic and cultural context and genesis.