"Sir Peter Russell, who has died aged 92, was the most influential 20th century English-speaking scholar of Iberian letters. As King Alfonso XIII professor of Spanish and director of Portuguese studies at Oxford for nearly three decades, in his published work he time and again challenged received wisdom, while using an intimate knowledge of his university and a worldwide network of friendships to promote the study of Spanish and Portuguese literature and history. Russell was born in Christchurch, New Zealand, coming to England as a boy with his mother and younger brother, Hugh, the epidemiologist who died earlier this year. The voyage took them via the Panama Canal and involved running the gauntlet of the German navy, kindling in the brothers a taste for travel and adventure. Educated at Cheltenham College and Queen's College, Oxford, Russell graduated in 1935 and began research on the intervention of the Black Prince in Spain and Portugal. The result, a magisterial survey of Western Europe in the late 14th century, was not published until 1955, but two shorter studies that sprang from it established what was to become a pattern: primary historical research informed literary criticism, while the historical perspective took account of literary recourses and how original documents were produced. Russell's travels in Europe in the 1930s had alerted him to the dangers of fascism. Recruited into the secret services in mid-decade, he monitored developments in Spain before the civil war of 1936-39, and in 1940 was commissioned into the Intelligence Corps. His first assignment was to shepherd the Duke and Duchess of Windsor from Madrid to Estoril in Portugal en route to the Bahamas, and ensure they were not waylaid by German agents. He later saw distinguished service in the Caribbean, West Africa and the Far East. Russell had been made college lecturer at St John's, Oxford, in 1937 and at Queen's the following year. After demobilisation in 1946, he was appointed university lecturer and fellow of Queen's. The story goes that, when his Spanish teacher William Entwistle died in 1952, the then vice-chancellor, Sir Maurice Bowra, dismayed by the field, pleaded with Russell to put his name forward at the eleventh hour. He did so, and was elected. To some it seemed a puzzling choice: Russell was still in his thirties and, thanks to his war service, had published little. It proved an inspired appointment. Advertisement In 1951 Russell astounded an audience by demonstrating that the Cantar de Mio Cid was not, as believed, the work of an early 12th century minstrel, but of a learned poet writing a century later. It was decades before his conclusions were generally accepted, especially in Spain, but the evidence he had amassed was incontrovertible and the significance of his arguments would be marked a half-century later by a volume published to celebrate the author's 90th year. Russell's 1960 lecture on the personality cult of the Portuguese soldier-prince Henry (1396-1460) met with similar hostility, yet few would now question its conclusions, expanded in his last full-length study, Prince Henry "the Navigator": A life (2000). Work on other Spanish masterpieces, among them Don Quixote and the late 15th-century work Celestina, of which he produced an edition (1991), also changed minds and laid down lines for research. His literary essays were collected in 1978 as Temas de la Celestina y otros estudios (del Cid al Quijote) and his historical studies in 1995 under the title Portugal, Spain, and the African Atlantic. Russell was also responsible for the best single-volume primer on Spanish letters, Spain: A Companion to Spanish Studies (1973), and much else besides. For several years after retirement in 1981, he lectured at US universities. Russell's working assumption that intelligent young scholars, properly supported and motivated, might be relied upon to get on with their research for themselves, was vindicated time an