The Irish-born Robert Stewart had a highly influential career in British politics and foreign service. He played a key role in subduing the Irish rebellion of 1798 and in the Act of Union of 1800. At that time, he was criticized for his mild approach toward the Irish and his tolerance for Catholicism. Later he was associated with harsh repressive measures, especially as memorialized in Percy Bysshe Shelley's poem "The Mask of Anarchy." He became the 2nd Marquess of Londonderry in 1821, following the death of his father, the 1st Marquess. In 1822, suffering from psychological distress associated with overwork, he committed suicide.