Complex sentence: Adam spent the rest of his life and career in relative obscurity; in 1423 he was incumbent of St Cybi's Church, Llangybi, Monmouthshire, near to his birthplace.
Split into simpler sentences: Adam spent the rest of his life and career in relative obscurity. In 1423 he was the incumbent of St Cybi's Church, Llangybi, Monmouthshire, near his birthplace.