Brownlow (Chamberlain), Arthur (1645–1711), landowner in Armagh and MP, was born 20 March 1645 at Ardee, Co. Louth, eldest son of Patrick Chamberlain of Nizelrath, Co. Louth, and Lettice Chamberlain (née Brownlow). His mother, who had three later marriages, was daughter of Sir William Brownlow, from whom Patrick Chamberlain's son Arthur, then at TCD, inherited in 1661 large estates in Co. Armagh. He adopted his grandfather's surname along with his father's, and from 1667, after studying law in Lincoln's Inn, he administered his lands in Armagh and Louth with great success. His policy of encouraging the linen industry among his tenantry resulted in increased prosperity for the region as well as for himself; he invested in land elsewhere, including Dublin, and planned the rebuilding of the town of Lurgan. The development of his estates can be traced in a manuscript leasebook, with entries from 1666 to 1708, which is of unique significance for seventeenth-century Ulster history.
Brownlow's focus was on maintaining and improving his estates during almost fifty years of great upheaval in Ulster, and his career in the public service – as high sheriff in 1679 and 1686, and as MP for Co. Armagh 1692–1711 (and also in the 1689 parliament of James II (qv)) – was subservient to that effort. In the first parliament of William III (qv) his having sat in the Jacobite parliament was criticised by people with an eye on his estates; but he defended himself eloquently. His interest in his locality, and perhaps his Chamberlain connections, led to an awareness, untypical in his class and period, of earlier Irish history and of Irish-language material. He was able to translate Irish poetry into English, and he is known to have owned at least a dozen manuscripts, including the important ninth-century Book of Armagh, and may well be responsible for their survival. He was also interested in geology, reporting on Lough Neagh's petrifying properties to the Dublin Philosophical Society in 1685, and was contacted by visiting antiquaries and scientists. He and his wife, Jane, daughter of Sir Standish Hartstonge of Co. Limerick, had five sons and two daughters, and at his death, on 20 March 1711, he left his successors a much enhanced patrimony in a locality that owed much of its modernisation and prosperity to his diligence.