Matthew of Edessa (second half of 11th century–1144) was an Armenian historian from Edessa His history "Chronicle" covers the first half of the 9th century through second half of the 12th. The work is in three parts. The first part covers the period 951–1051. The second covers 1051–1101, and the third covers up to 1129, with some material up to 1136 that may have been done by a collaborator. While the first two parts are a broader history of Byzantine and Caucusus affairs, the third part focuses exclusively on Edessa and its environs. Two parts of the Chronicle have received particular attention. The first is a letter from emperor John I Tzmiiskes to king Ashot III of Armenia in 975 and the second is a discourse from exiled king Gagik II of Armenia to Constantine X Doukas after 1045 on the divergence of the Greek and Armenian churches. The work was continued after his death, believed to be during the siege of Edessa, by Gregory the Priest. (RHC Ar., Volume 1, Runc. Vol I, pp. 335–336, 349, Runc. Vol II, p. 483)