Carlo della Torre di Rezzonico, was born on March 7, 1693 in Venice. He was educated by the Jesuits and supported that order throughout his pontificate, from 1758 to 1769.
His connection to the story of Catholics in England after the English Reformation is that he recognized the Hanoverian monarchs after the death of James III (the Old Pretender, James Francis Edward Stuart) on January 1, 1766. Clement honored King James with a great state funeral on January 8, but would not recognize his son, Bonnie Prince Charlie, Charles Edward Stuart, who failed in the best opportunity the Jacobites had, the '45, as the Stuart claimant to the throne of England, Ireland, Scotland and Wales.
King George III may have been encouraged to sign the Papists Act of 1778, which included an oath that abjured the Pretender, and the Roman Catholic Relief Act of 1791, but he would not go any further than that. He was concerned that he would be violating his coronation oath to protect the Church of England.
On the other hand, Henry Cardinal Stuart, the Young Pretender's younger brother, was unhappy with the pope's "betrayal" of the Jacobite cause. He seems to have become reconciled however, to this change, and concentrated on fulfilling his duties as Cardinal York. As for the Young Pretender, he even thought about being an Anglican to try to assert his claim to the throne!