Complex sentence: He then rowed across lake Mjøsa to Toten, capturing residents, impresioning them in the vaoulted cellar of the rectory in Østre Toten and torturing them there to establish that Bishop Karl of Hamar had been behind the rebellion.
Split into simpler sentences: He then rowed across lake Mjøsa to Toten, capturing residents, imprisoning them in the vaulted cellar of the rectory in Østre Toten and torturing them there. As a result, he determined that Bishop Karl of Hamar had been behind the rebellion.