 With Mary's accession in 1553, and the re-establishment of Roman Catholicism in Ireland, Dowall was reappointed to the see of Armagh, this time with the Pope's approval, and he held the position until his death, some three months before Mary's.He was energetic in attempting to undo the effects of the Reformation, holding two provincial synods at Drogheda to restore the constitution of the pre-Reformation Church.He was particularly zealous in depriving married clergy of their livings, and as a result was accused of taking the opportunity to persecute his personal enemies, such as George Browne, Archbishop of Dublin.