In early 1673, English politics was destabilised by the prospect of a Catholic monarch when Charles' heir and younger brother James, Duke of York publicly confirmed his conversion. For the next 18 months, a small group of peers led by Holles and Shaftesbury constantly attacked him in the Lords, but this changed in 1675. Fearing Parliament was about to enact new measures against Catholics and English Dissenters, James proposed pardons for anyone convicted under the Conventicles Act. This initially won him the backing of Holles, until Charles demanded he withdraw the idea.