Complex sentence: Thereafter his career advanced rapidly: he became Third Serjeant in 1817, Second Serjeant in 1818, and a judge of the Court of King's Bench (Ireland) in 1820: he was one of the last Englishmen to be elevated to the Irish Bench.
Split into simpler sentences: Thereafter his career advanced rapidly: he became Third Serjeant in 1817, Second Serjeant in 1818, and a judge of the Court of King's Bench (Ireland) in 1820. He was one of the last Englishmen to be elevated to the Irish Bench.