well as an attempted assassination by the Varangian Guard. Nikephoros embraced the trappings of an emperor, performing many acts to increase his legitimacy and support, such as spending large amounts on donatives for the army and his supporters, forgiving all debt in arrears, and instituting minor legal reforms. Diplomatically, Nikephoros secured the submission of Theodore Gabras and Philaretos Brachamios, governors of Trebizond and Antioch, respectively, who had become de facto independent of the Byzantine Empire due to the constant incursions of the Seljuks into Byzantine Anatolia. In 1081, the Norman Duke Robert Guiscard of Apulia prepared to invade the Byzantine Empire under the pretext of defending the succession of Constantine Doukas, who had been engaged to Robert's daughter Helena. Alexios I Komnenos was entrusted with an army and sent to defeat the Norman threat, but instead conspired with his relative John Doukas to seize the throne. Alexios raised a rebellion against Nikephoros and was able to quickly encircle Constantinople and besiege it, due to the lack of a defensive army. Nikephoros was unable to secure the support of either the Seljuk Turks or Nikephoros Melissenos, his traditional rivals, and therefore was forced to prepare for abdication. Nikephoros decided that his only choice was to abdicate in favor of Melissenos, who was nearby in Damalis in Anatolia, and sent messengers to him across the Bosphorus; however, these messengers were intercepted by George Palaiologos, a general of Alexios, who persuaded them to support Alexios. Alexios and his forces broke through the walls of Constantinople on 1 April 1081. Nikephoros fled and sought sanctuary inside of the Hagia Sophia, while Alexios' troops sacked the city for three days. Nikephoros was taken from there to the Monastery of Peribleptus, where he abdicated and became a monk. Historiography and sources The most comprehensive account of Nikephoros III's life and reign is The History, written in the 1070s by the Byzantine historian Michael Attaleiates and dedicated to Nikephoros himself. Attaleiates is the primary contemporary source for Nikephoros's reign and counters the narrative of Byzantine historian Michael Psellos's Chronographia, the only other contemporary source. Attaleiates highlights Nikephoross achievements, often containing records of his actions which no other source mentions, such as his eleven-day rearguard command after the Battle of Zygos Pass, to which Attaleiates dedicates several pages. Attaleiatess high opinion of Nikephoros was likely shaped by Nikephoros raising him to the rank of vestes, and by his