Complex sentence: The schism continued for four years until Theodoric withdrew his support of Laurence, deciding that the adherents of Laurence were too pro-Byzantine, and had him removed from Rome, so that opposition to Symmachus eventually was stilled.
Split into simpler sentences: The schism continued for four years until Theodoric withdrew his support of Laurence. Eventually, Theodoric, deciding that the adherents of Laurence were too pro-Byzantine, had him removed from Rome, and opposition to Symmachus eventually was stilled.