Complex sentence: Henry's subsequent execution of England's premier cleric, comparable with the murder of Thomas Beckett, would probably have led to Henry's excommunication but the church was in schism, with two competing popes keen on Henry's support, and protested but took no action.
Split into simpler sentences: Henry's subsequent execution of England's premier cleric, comparable with the murder of Thomas Beckett, would probably have led to Henry's excommunication. However, the church was in schism with two competing popes keen on Henry's support; it protested but took no action.