Complex sentence: The apostolic vicar Sasbout Vosmeer tried to have Gérard canonized, to which end he removed the dead man's head and showed it to church officials in Rome, but the idea was rejected.
Split into simpler sentences: The apostolic vicar Sasbout Vosmeer tried to have Gérard canonized. He stole Gérard's head and showed it to church officials in Rome, but the idea was rejected.