Complex sentence: Since Mabel wished for a Protestant ceremony, Jones was summoned to Drumcondra Castle, where the couple had taken refuge, by its owner Sir William Warren, and persuaded with great reluctance to perform the marriage, largely, it seems, to protect Mabel's reputation.
Split into simpler sentences: Since Mabel wished for a Protestant ceremony, Jones was summoned to Drumcondra Castle, where the couple had taken refuge, by its owner Sir William Warren. The Bishop was persuaded although only with great reluctance to perform the marriage, largely, it seems, to protect Mabel's reputation.