Windham Thomas Wyndham-Quin was the 4th Earl of Dunraven and Mountearl. His family was one of the very few families of Celtic origin in the Irish peerage as they were initially chiefs of the Clan of Hy-Ifearnan.
He was born in Adare, which he later made his home and was educated privately at Rome and Christ Church in Oxford. He eventually joined the Life Guards in 1862 and was a war correspondent for the Daily Telegraph in Ethiopia in 1867 and the Franco-Prussian War in 1870. For a period he lived in America and was a US civil War Correspondent before he succeeded to the earldom.
He was renowned for taking a great interest in Irish political affairs. During 1885-1887 he chaired the Commission on Sweated Labour and Outlook for Ireland, The Case for Devolution and Conciliation 1897-1907. In 1905 he advocated devolution of legislation to an Irish parliament and at the Irish Convention in 1917, he proposed a federal solution. W.T. Cosgrove nominated him to the Seanad of the Irish Free State in 1922.
In addition to this, he contributed to his mother, Caroline, Countess of Dunraven's Memorials of Dunraven, wrote The Irish Question in 1880, and his memoirs Past Times and Pastimes.
Wyndham-Quin appears to have been a social acquaintance and prospective client of Whistler; he was invited to lunch on 20 June 1884 and on 28 June 1884 he wrote to Whistler about three works including Red and Black, which he was unable to afford. Whistler had reservations about the position of the peerage in Ireland, and his jokes about extorting money from the Irish peasantry may not have endeared him to the Earl.
Debrett's Peerage and Baronetage, London; Burke, E., The Peerage and Baronetage of Great Britain and Ireland, London, online.