Tacitus ascend the annals of power at the age of seventy-five. He tried to make many legislative reforms regarding the senate. During his rule a new barbarian group the Alani menaced the empire. Like a good statesmen, Tacitus was able to convince some of them to go back home without a struggle. The rest were forcibly removed or wiped out. The aged emperor died in only two years under mysterious circumstances. Some say he was killed by the soldiers who did not appreciate his new legal reforms, others contend it was of natural causes.

Power first went to his brother Florianus who was universally despised by not respecting the senates authority. A gifted general in the east, Probus then forcibly sized power from Florianus.