Complex sentence: Tihomir was also proclaimed Emperor in his own right separate from Delyan, who knew that the existence of two separate rebel leaders and camps would be problematic for the revolt and invited Tihomir to a meeting.
Split into simpler sentences: Tihomir was also proclaimed Emperor in his own right separate from Delyan. Delyan knew that the existence of two separate rebel leaders and camps would be problematic for the revolt and invited Tihomir to a meeting.