Complex sentence: Thomas Bradwardine, later briefly Archbishop of Canterbury, was Rector of Llanbadarn Fawr 1347-1349, and thereafter the Abbot of the Cistercian Vale Royal Abbey, Chester, was ex officio Rector 1360-1538.
Split into simpler sentences: Thomas Bradwardine, later briefly Archbishop of Canterbury, was Rector of Llanbadarn Fawr 1347-1349. Thereafter the Abbot of the Abbey was ex officio Rector 1360-1538.