Complex sentence: Anacletus' supporters were a mixture of anyone opposed to Haimeric making him powerful enough to take control of Rome while Innocent was forced to flee North; legally speaking Anacletus was the canonically elected Pope and Innocent was the anti-Pope.
Split into simpler sentences: Anacletus' supporters were a mixture of anyone opposed to Haimeric making him powerful enough to take control of Rome while Innocent was forced to flee North. Legally speaking Anacletus was the canonically elected Pope and Innocent was the anti-Pope.