His father (or possibly grandfather), of the same name, the governor of the theme of Dyrrhachium, had revolted against the feeble Michael VII, but had been defeated by the future Emperor Alexios I Komnenos.
The marriage of Nikephoros the Younger was probably arranged during the Cuman War of 1094, when Alexios needed the support of the Bryennios family and their abilities to mobilise the military potential of Thrace.
This was more of a demonstration than a serious conflict, as the Byzantine defenders were ordered to shoot the Crusaders' horses, to avoid killing Christians on a holy day.
[7] His wife attributed his refusal to cowardice, but it seems from certain passages in his own work that he really regarded it as a crime to revolt against the rightful heir; the only reproach that can be brought against him is that he did not nip the conspiracy in the bud.
As might be expected, his views are biased by personal considerations and his intimacy with the royal family, which at the same time, however, afforded him unusual facilities for obtaining material.