Mason, Henry Joseph Monck (1778–1858), miscellaneous bilingual writer, librarian, and evangelical reformer, was born 15 July 1778 at Powerscourt demesne, Enniskerry, Co. Wicklow, son of Lt-col. Henry Monck Mason and his second wife, Jane, only daughter of Bartholomew Mosse (qv), distinguished surgeon, philanthropist, and founder of the Rotunda Hospital, Dublin. Mason's family was distinguished by several generations of military, parliamentary, and scholarly achievement, and his brother William (qv) was a noted collector of books.
Mason was educated in Portarlington and Dublin before entering TCD (1793). He was elected scholar (1796), graduated BA with a gold medal (1798), and became a barrister (1800) but never practised. Instead, he served as prerogative court examiner until 1810–12, when he became a librarian, following a request by the public record commissioners to create a draft catalogue of TCD's manuscript collection. It was incomplete by 1814, when he was appointed assistant law librarian at King's Inns, Dublin, and chief librarian in 1815. In June 1812 he was elected MRIA, sat on the antiquities committee, and contributed to Transactions. He married (1816) Anne, daughter of Sir Robert Langrishe (qv), and lived many years in the library building, where they raised two sons and four daughters.
His active interest in the Irish language developed early in his career, and he engaged the scholar Edward O'Reilly (qv) to assist with the Gaelic manuscripts at TCD. He respected Irish as the language of the people and developed a network of like-minded scholars. The other side to his interest was the anglican evangelisation of the catholic, Irish-speaking population, most numerous in the west of Ireland. With Robert Daly (qv) (later bishop of Cashel and Waterford), and other lay and religious contemporaries, he was founder secretary in 1818 of the Irish Society (‘for promoting the education of the native Irish through the medium of their own language’), which had its headquarters at 16 Upper Sackville (later O'Connell) St., Dublin. The society aimed to remove the causes of poverty and convert through knowledge of scripture and the Book of Common Prayer, rather than by crude proselytisation.
TCD conferred Mason LLB and LLD in 1817. Increasingly, he published historical and religious treatises that referred to the aims of the Irish Society, sometimes exceeding his own limited knowledge and expertise. He earned as much barbed criticism as praise, but owing to a want of modesty this failed to temper his self-confidence. In 1820 he published his Essay on the antiquity and constitution of parliament in Ireland, dedicated to Henry Grattan (qv) who died in that year. Tracing the Irish parliamentary legal tradition from medieval times to the seventeenth century, this well received work (reprinted within a new prefaced edition in 1891) was intended as the first volume of a longer history of parliament extending to the act of union (1800); it remained unfinished.
During the 1820s Mason wrote a number of Irish Society pamphlets and articulated growing demand for prison reform, having helped (also in 1818) to establish the Association for the Improvement of Prisons and of Prison Discipline in Ireland. While truly concerned about reform, he remained adamant about the importance of religious propagation through Irish, rather than English, the language of business and commerce. He edited the Book of Common Prayer (1825) in Irish, wrote widely on early Irish sainthood, and published The Lord's prayer: a poem (1829). His Grammar of the Irish language (1830) was more literary than vernacular and therefore of little popular appeal. However, it received negative criticism when in a letter to the Christian Examiner of September 1833 Mason picked faults in the Irish prayer book edited by Owen Connellan (qv), historiographer-royal, distinguished Gaelic scholar, and librarian at the RIA. Mason's moment of hubris rebounded on him with Connellan's reply, which exposed errors in Mason's Grammar and expressed a similar opinion of the Irish Society's 1830 edition of the Irish Bible of Bishop William Bedell (qv). It was damaging in that other Gaelicists including John O'Donovan (qv) of the ordnance survey supported Connellan. Mason's enthusiasm was undaunted and in 1836 he chose to dispute, perhaps with greater justification, aspects of the History of Ireland (1827) by the poet Thomas Moore (qv). He published his Life of William Bedell D.D., lord bishop of Kilmore in 1843, redressing some of the academic ill-fame brought by the Grammar.
Mason was largely responsible for establishing a chair of Irish at TCD; in addition two Bedell scholarships were founded at his suggestion in 1844 by the Irish Society, and a premium offered to encourage Irish-language study. By the late 1840s Irish-speaking had declined sharply, accelerated by the great famine, but those in receipt of instruction by the Irish Society had risen more than sixfold since its foundation to c.18,000 people. However, Mason's evangelical endeavours through Irish succumbed to historical forces outside his control, not least emigration. He retired from the King's Inns in 1851, vacating his home on Henrietta St., and moving to Dargle Cottage near Bray, Co. Wicklow. A brief alliance with the blatantly proselytising Irish Christian Missions (ICM) in the early 1850s was terminated owing to the Irish Society's discomfort with the ICM's methods. Mason compiled some of his old Christian Examiner articles in 1854 under the title Memoir of the Irish version of the Bible. His interests extended to musical composition and he was an accomplished cellist. He died at home 14 April 1858 and was buried near his birthplace on the Powerscourt estate.