Complex sentence: He strongly disputed the claim that freedom from God's punishment for sin could be purchased with money, proposing an academic discussion of the power and usefulness of indulgences in his "Ninety-five Theses" of 1517.
Split into simpler sentences: He strongly disputed the claim that freedom from God's punishment for sin could be purchased with money. He proposed an academic discussion of the power and usefulness of indulgences in his "Ninety-five Theses" of 1517.