When in 2009 experts at the Prado Museum in Madrid attributed their famous painting The Colossus to one of Francisco Goya's assistants rather than Goya himself, my friend and colleague Nigel Glendinning returned to an argument that had been rumbling on for eight years. An international authority on the artist, he stoutly defended the authenticity of this startling work on grounds of historical documentation and artistic style, contributing to the still unresolved controversy in his typically forthright but courteous and humorous way.
Nigel, who has died aged 83, began writing on Spanish art while he was a lecturer at Christ Church, Oxford. As a result, in 1963 he was involved in the Royal Academy exhibition Goya and His Times, providing catalogue entries for the portraits. Goya and His Critics (1977) and Nigel's subsequent books and articles established him as an authority not just on the portraits, but on Goya's print series, especially the Caprichos and Disparates, and on the 14 Black Paintings of 1819-23.
His first book, published in Spain in 1962, was Vida y Obra de Cadalso, an account of the life and work of the Enlightenment writer José de Cadalso. The volume on the 18th century that he provided for A Literary History of Spain (1972) went on to appear in many Spanish editions and revisions.
Born in East Sheen, south-west London, Nigel, whose father was a bank manager, began a lifelong interest in music as a chorister at St Paul's Cathedral. On leaving St John's school, Leatherhead, in Surrey, he undertook national service in the Royal Army Educational Corps. In 1950 he went to King's College, Cambridge, to study French and Spanish, and wrote his doctoral thesis on Cadalso.
At the age of 33 Nigel left Christ Church for Southampton University as professor of Spanish. In 1970, he went to Trinity College Dublin, and four years later to what is now Queen Mary, University of London, where he remained until retiring as professor emeritus in 1991.
Nigel received numerous Spanish honours, particularly for doing so much to revive Enlightenment studies there, and was appointed commander of the Order of Isabel la Católica. He was the kindest and most generous of colleagues.
In 1958 he married Victoria Seebohm, who has continued to write as Victoria Glendinning since their divorce in 1981. He is survived by their four sons, Paul, Hugo, Matthew and Simon.