Complex sentence: He had the oak felled to prove the superiority of the Christian god over Thor and the Germanic deities, and when Thor did not respond by hurling a lightning bolt at him, the assembled local people agreed to be baptized.
Split into simpler sentences: He had the oak felled to prove the superiority of the Christian god over Thor and the Germanic deities. When Thor did not respond by hurling a lightning bolt at him, the assembled local people agreed to be baptized.