Complex sentence: On the death of Archbishop Laurence in 1838, the Church of Ireland Province of Cashel was united to the Province of Dublin and the episcopal see ceased to be an archbishopric; becoming the bishopric of Cashel and Waterford.
Split into simpler sentences: On the death of Archbishop Laurence in 1838, the Church of Ireland Province of Cashel was united to the Province of Dublin. The episcopal see ceased to be an archbishopric becoming instead the bishopric of Cashel and Waterford.