Scully, Denys (1773–1830), political writer and champion of catholic emancipation, was born on 4 May 1773, seventh child and second son of James Scully (1737–1816), a prosperous grazier who in 1780 settled at Kilfeacle, Co. Tipperary, and his wife Catherine Lyons, of Croome House, Limerick. He attended Kilkenny Academy (later known as St Kieran's College), and was destined for mercantile life, but the catholic relief act of 1792 afforded the opportunity to study for the bar. In 1794 he entered Trinity College, Cambridge, as a pensioner, one of the first catholics that contemporaries could remember to have attended the university. In 1796 he was called to the Irish bar, and began to practise in 1798. He joined the Leinster circuit, but failed to shine as an advocate and apparently became a consultant on property matters, specialising in the effects thereon of the penal laws.
Scully married (1801) Mary Huddleston of Sawston Hall, Cambridge, a member of an old, though impoverished, English catholic family. She was a neighbour of Lord Hardwicke (qv) (lord lieutenant of Ireland 1801–5), and once settled in Baggot St., Dublin, the Scullys were invited to levées at Dublin Castle (James Scully had used his electoral influence in Tipperary to support the act of union).
During the French wars Denys Scully served in the Lawyers' Corps of Yeomanry. He was critical of the rebellion of Robert Emmet (qv), and published a pamphlet, entitled An Irish catholic's advice to his brethren, how to estimate their present situation and repel French invasion, civil wars and slavery (Dublin, 1803), urging his fellow countrymen to oppose the French. His first public involvement with the catholic question came in late 1804, when he attended a series of private catholic meetings in Dublin. He was appointed to a sub-committee (along with Daniel O'Connell (qv)) to draw up a petition to parliament for the abolition of the remaining penal laws, and served on the deputation that took the petition to London. Although the prime minister, Pitt, declined to endorse it, Scully furthered his contacts with opposition politicians, to whom the petition was subsequently entrusted. Following the rejection of the petition by parliament in May 1805 catholic agitation in Ireland took a more populist form under the merchant John Keogh (qv). Scully remained in the background for some years, the death of his wife in 1806 and departure of Lord Hardwicke having weakened his links with the Castle. His second marriage (1808), to Katherine (1784–1843), daughter of Vincent Eyre (1744–1801) of Sheffield Park, near Sheffield, and his wife Catherine (1757–1820), was apparently arranged by Dr John Milner, vicar apostolic of the English midland district and confidant of the Irish bishops during the veto controversy.
In 1808 Scully proposed the formation of a Catholic Society to raise funds, but this came to nothing. However, around this time he did organise a catholic committee in Co. Tipperary with a view to a nation-wide movement. In 1809 he joined the General Committee of Catholics and helped prepare the petition to parliament of 1810, which was presented to the house of lords by Scully's Tipperary neighbour, Lord Donoughmore (qv). He was centrally involved with the committee's attempts, in defiance of the 1793 convention act, to organise a representative catholic assembly, a strategy that met with some success during 1811. And it was to him in that year that William Parnell (qv) of Avondale first outlined a plan (implemented so successfully in the 1820s) for raising a ‘catholic rent’ from all classes of catholics (Scully papers, letter 314). Scully published anonymously his most important work, A statement of the penal laws which aggrieve the catholics of Ireland, in two parts (Dublin, 1811–12). It was well received, but earned the publisher, Hugh Fitzpatrick (qv), a term of imprisonment for a libel in a footnote in part II. During 1812 Scully persuaded Tipperary and Dublin catholic freeholders to withhold support from parliamentary candidates who supported any ministry hostile to emancipation. The cause was boosted in 1812 when the incoming prime minister, Lord Liverpool, made emancipation an open question for cabinet members, and in May 1813 an emancipation bill almost passed the committee stage in the house of commons. However, it contained provision for government ‘securities’, which proved divisive both for English and Irish catholics. In Ireland the Catholic Board split over the issue: Scully sided with the Irish bishops against the securities, but many of the more moderate catholics withdrew from the agitation. Scully's militancy at this time was reflected in his drafting of the ‘Kilkenny resolutions’ of August 1813, which were interpreted by the chief secretary, Robert Peel (qv), as implying that Fitzpatrick's trial had represented a miscarriage of justice.
The following years were bedevilled by divisions over the securities (‘veto’) issue. There was friction with some old allies in parliament, including Lord Donoughmore, who blamed Scully for criticism of him in a new pro-emancipation newspaper, the Dublin Chronicle, which Scully supported with money and his pen. But by 1817 Scully was distracted from politics by personal matters. His father had died in 1816, leaving Denys and his brother James as executors of his will, but the will was challenged by his widow, leading to a prolonged legal dispute, which was settled against the executors in 1825. Scully maintained his interest in the catholic question, but apparently played no part in the conduct of affairs after about 1820. In 1823 he suffered a fit of apoplexy which ended his career on circuit. He died at Kilfeacle on 25 October 1830, leaving five sons and three daughters, and was buried in the family grave on the Rock of Cashel.
Although his contribution to the campaign for catholic emancipation has been obscured by the later ascendancy of Daniel O'Connell, Scully made a major contribution to the catholic cause, particularly in the period of the Napoleonic wars.