Like others of his generation he was a polymath whose interests and research ranged from the prehistoric periods through to the Roman Empire and into the Middle Ages, and thence to more recent aspects of Balkan folk art. He was essentially international in outlook, with a profound knowledge of European sites and antiquities.
A student at the British Schools of Archaeology at both Athens and Rome, he was subsequently to become Director of the British School at Rome (1936- 39). It was, however, in exploring the nature of Celtic monasticism together with the physical traces of early Christianity and its subsequent organisation during the early medieval period across the British Isles that Radford was a pioneer. He once declaimed at a conference in Orkney, "I am a Christian archaeologist."
Coming from a Devon family and with a father who was also a medievalist and fellow of the Society of Antiquaries of London, he was given traditional Devonshire names of Courtenay and Ralegh as well as Arthur, which was to be doubly significant as his interests developed. At the age of 10 his father took him to the excavations at Glastonbury and this was to influence his future.
He read History at Exeter College, Oxford, and it was while still an undergraduate that he excavated the Pinhoe Mound near Exeter and collaborated with the then Chief Inspector of Ancient Monuments, C.R. Peers, at the excavations at Whitby Abbey. It was the beginning of a lifelong association with monuments in state care. After further travel in the Balkans and the excavation of the Westland Roman villa, Yeovil, Radford joined the Inspectorate of Ancient Monuments, Office of Works, in 1929 becoming Inspector for Wales.
Outside Wales he was continuing to excavate sites mainly in Devon and Cornwall although the Roman villa of Ditchley, Oxfordshire, figured strongly. He is especially noted for his work at Tintagel, which he believed to be a Celtic monastic site. Although some of his interpretations have been challenged by a later archaeological generation, his excavations at Tintagel and Castle Dore were highly significant in their day.
He was the first to identify the imported eastern Mediterranean pottery which established the date of the settlement on the headland at Tintagel to the fifth and sixth centuries AD. Excavation, however, was not the only aspect of his fieldwork. In 1936-37 he accompanied Mortimer Wheeler in a reconnaissance of the late prehistoric hill-forts of northern France for a research programme which was to be aborted by war.
Since the Fascist authorities did not allow foreign-run excavations in Italy, Radford, as Director of the British School at Rome, continued with his British projects. He did nevertheless begin a new publication series at the school and supervised the completion of the south wing of the Edwin Lutyens-designed building.
There is a photograph of Radford in the school courtyard standing alongside Neville Chamberlain and Lord Halifax who had turned from their post-Munich deliberations with the Italian government to make a visit. At the outbreak of war in 1939 Radford had to close down the school which involved much burning of papers in the courtyard.
He returned to Britain to work first in the BBC, then in the intelligence department of the Foreign Office, becoming Chief Intelligence Officer in the department of psychological warfare at Allied HQ in Algiers. He carried the rank of a staff Colonel.
After the war Radford returned to direct more excavations in the West Country before taking over the excavations at Glastonbury in 1951. Briefly, from 1946 to 1948, he was acting Secretary of the Welsh Royal Commission of Historical and Ancient Monuments. His activities then spread to Scotland, where he worked at Whithorn Abbey and other early Christian sites before being invited to Orkney to investigate the Norse settlement of Birsay.
He was later to excavate at Peel Castle on the Isle of Man. His particular interest in early Christianity and what was then termed the Dark Ages led him deeply into Arthurian studies. It was unsurprising that he was one of the instigators in 1965 of the excavation of South Cadbury hill- fort in Somerset with its Arthurian associations.
All the while he produced a torrent of learned papers, excavations reports and guidebooks to national monuments. His versatility and intellectual power had already brought him fellowship of the Society of Antiquaries at the precocious age of 28. He was eventually to receive its highest award, the society's gold medal, in 1972 and honorary doctorates at three universities. He was elected to the British Academy in 1956 and was a member of the German Archaeological Institute. He was given no fewer than three Festschrifts, including one at 80 (The Early South Western Church in West Britain and Ireland, 1982), and another at 90 (The Archaeology and History of Glastonbury Abbey, 1991).
Radford's broad experience and practical involvement with the preservation and interpretation of monuments made his advice widely sought in official as well as archaeological circles. He served as a member of both the Royal Commissions on Historical Monuments for England and Wales and on the three Ancient Monuments Boards for England, Wales and Scotland. These were advisory bodies providing archaeological advice to the respective Ancient Monuments Inspectorates and reporting to ministers.
Few individuals have been in such demand before or since. He served as President of the Royal Archaeological Institute, of the Cambrian Archaeological Association, the Prehistoric Society and the Medieval Society and more locally of the archaeological societies of Cornwall, Devon and Somerset, the Royal Institution of Cornwall and many local historical societies. He was always courteous and businesslike, as much at home in the committee room as on an excavation. His erudition was formidable, which could make him intimidating, but he was always stimulating. He could be, in the words of Stewart Cruden, "remorselessly informative". To the last he maintained his independent spirit, refusing medication unless accompanied by sherry.
Ralegh Radford was one of the great figures of 20th-century archaeology, never insular in viewpoint and with remarkable intellectual versatility, lecturing, contributing to discussions on site and at conferences. He will always be remembered standing before his audience, eyes closed, rocking from side to side and speaking in a high-pitched clerical voice. It was enthralling stuff and if on later reflection one began to question some of the content, the imagination had been fired and one was all the wiser.
Courtenay Arthur Ralegh Radford, archaeologist: born Hillingdon, Middlesex 7 November 1900; FSA 1928; Director, British School at Rome 1936-39; OBE 1947; FBA 1956; died Uffcolme, Devon 27 December 1998.