Betham, Sir William (1779–1853), archivist and scholar, was born 22 May 1779 at Stradbrooke, Suffolk, eldest surviving son among fourteen children of William Betham (d. 1839), clergyman and antiquary, and Mary Betham (née Damant). He was apprenticed to a printer, was employed to revise part of Camden's Britannia for republication, and assisted his father with genealogical work till a disagreement between them left him almost destitute. He visited Dublin in 1805 to search for documents necessary for a law case, and found that the archives in the record tower of Dublin castle were badly neglected. On appealing to the keeper of the records (Philip Stanhope, Viscount Mahon), he had himself appointed Mahon's deputy. He also became (1807) deputy Ulster King of Arms, and spent a lifetime in arranging documents and preparing valuable indexes, thus greatly facilitating historical and genealogical researches in Ireland. The work, however, was not without conflict and frustration. His relations with the Irish record commission (1810–30), and especially its secretary, W. Shaw Mason (qv), deteriorated rapidly from 1812, and he made a series of complaints of insufficient funding and staffing (he claimed he was obliged to fund the work from his own resources) and poor management of archives. He advocated the creation of a central repository for all records; the building of the PRO beside the Four Courts was completed fourteen years after his death. For fifty years he was involved with many aspects of public life in Dublin, presiding over public bodies and charities. He was knighted (1812) and made Ulster King of Arms (1820), was elected FSA of London (May 1824) and MRIA (1826), and served as the Academy's secretary for foreign correspondence (1828–39).
Betham developed somewhat speculative theories on Irish antiquities and linguistic history, which he outlined in several books including Etruria Celtica: Etruscan literature and antiquities investigated, or the language of that people compared and identified with the Iberno-Celtic, and both shown to be Phoenician (1842). As early as 1826 his antiquarian researches were criticised by Thomas L. Cooke (qv), and his belief that round towers were Phoenician in origin was overturned by the work of George Petrie (qv). When the RIA awarded Petrie a gold medal for his work on Tara, Betham was so incensed that he involved the lord lieutenant in the controversy, and subsequently (1840) resigned from the council of the Academy.
This unfortunate episode, and his inexpert philological and archaeological speculations, should not detract from his achievements. As well as several valuable publications on constitutional history and his work in the record tower (where his abstracts survived when many of the original documents were lost in 1922), Betham collected almost 2,000 manuscripts and books, undoubtedly saving many of them from destruction. He purchased the Book of Dimma and the Book of Armagh, translated the latter with the help of Edward O'Reilly (qv), and discovered one of the most celebrated Irish manuscripts, the Cathach of St Columba (qv), hidden in what had been previously thought to be an empty casket. Many of his Irish-language manuscripts and books were bought by the RIA in 1850, and after his death (26 October 1853) other parts of his collection came to the office of Ulster King of Arms. He was buried in the old graveyard at Monkstown, Co. Dublin.
He married first (22 July 1802) Martha Norton of Suffolk (or Camberwell), who died a week after her baby daughter in September 1803; secondly (25 November 1805) Elizabeth, daughter of Cecil Crampton, rector of Headfort, Co. Galway. Her brother was Philip Crampton (qv), a justice of queen's bench; a cousin was Sir Philip Crampton (qv). Their children were Molyneux C. J. Betham, barrister and Cork Herald; Sheffield P. F. Betham, Dublin Herald; and two daughters. William Betham's sister Matilda Betham was a well known poet and author of a biographical dictionary of celebrated women.