The Annals of Tigernach (abbr. AT) is a chronicle probably originating in Clonmacnoise, Ireland. The language is a mixture of Latin and Old and Middle Irish. Many of the pre-historic entries come from the 12th-century MS, Rawlinson B 502. However, the real importance of the chronicle is for the period 489-766, 973–1003 and 1018–1178. These three fragments survive from the 14th-century MS Rawlinson B 488. The coverage of the period 766 to 973 is lost, but is thought to survive in abbreviated form in the Chronicon Scottorum (abbr. CT). The latter is defective for the period 718 to 804, but as much of its content is derived from the hypothetical Chronicle of Ireland (itself partly derived from the Iona Chronicle), of which the Annals of Ulster (abbr. AU) and Annals of Inisfallen (abbr. AI) ar