Complex sentence: Because the canons had arrived on the eve of the town's annual fair all the inns and lodging houses were full with merchants, but one group of merchants staying at a newly-built lodging house kindly vacated their rooms.
Split into simpler sentences: Because the canons had arrived on the eve of the town's annual fair all the inns and lodging houses were full with merchants. However, one group of merchants staying at a newly-built lodging house kindly vacated their rooms.