In 2E 864, the Redguards of Hammerfell rose in rebellion against the Imperial administration of Provincial Governor Amiel Richton. The Restless League, led by Cyrus and Iszara -- brother-and-sister agents of the province's hereditary rulers -- destroyed the Imperial fleet in Stros M'Kai harbor and routed the Legion garrison. With Admiral Richton dead, and Stros M'Kai in rebel hands, Emperor Tiber Septim was forced to sue for peace on terms favorable to Hammerfell.
"The Stros M'Kai uprising is the only military reverse during Septim's annexations of the Western provinces. An able strategist and administrator, Admiral Richton's misfortunes arose from over-confidence, unsuitable counselors, and inauspicious stars." -- from Jalba's WAR IN THE WEST