Complex sentence: After winning the case, Marquis promptly retired from that career so that he could claim that he was "100 percent successful as a lawyer", but he remained listed as a member of the Montana bar throughout his life.
Split into simpler sentences: After winning the case Marquis promptly retired from that career so that he could claim that he was "100 percent succesful as a lawyer". He remained, however, listed as a member of the Montana bar throughout his life.