Complex sentence: The Bagler faction which was made up of aristocracy, clergy and merchants contested with the Birkebeiners, essentially a faction of peasants, led by the pretender King Sverre, for control in a Norwegian civil war during the late 12th century.
Split into simpler sentences: The Bagler faction was made up of aristocracy, clergy and merchants. It contested with the Birkebeiners, essentially a faction of peasants, led by the pretender King Sverre, for control in a Norwegian civil war during the late 12th century.