Year 291 (CCXCI) was a common year starting on Thursday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Tiberianus and Dio (or, less frequently, year 1044 Ab urbe condita). The denomination 291 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.

Year 291 (CCXCI) was a common year starting on Thursday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Tiberianus and Dio (or, less frequently, year 1044 Ab urbe condita). The denomination 291 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.