Obituary: Professor Kenneth St Joseph

John Kenneth Sinclair St Joseph, historian: born 13 November 1912; Lecturer in Natural Sciences, Selwyn College, Cambridge 1939-62, Dean 1939- 45, Tutor 1945-62, Librarian 1946-62, Vice-Master 1974-80; Demonstrator in Geology, Cambridge University 1937- 45; Operational Researcher, Ministry of Aircraft Production 1942-45; member, Council for British Archaeology 1944-94; Lecturer in Geology, Cambridge University 1945-48; Leverhulme Research Fellow 1948-49; Curator in Aerial Photography, Cambridge University 1948-62, Director 1962-80; OBE 1964; member, Royal Commission on Historical Monuments (England) 1972-81; FBA 1978; CBE 1979; married 1945 Daphne March (two sons, two daughters); died Cambridge 11 March 1994.

KENNETH St JOSEPH developed the science of air photography, for scholarly and scientific purposes, in Britain. It was used before the Second World War but only, at Stonehenge for example, to a limited extent. But under St Joseph's lead it had astonishing success in the development of modern geology, soil science, geography; but especially in archaeology, from prehistoric to medieval: and above all in his own special love, the archaeology of Roman Britain. He transformed our knowledge of the early history of Scotland.

In 1939 he was a teacher of geology at Cambridge University and at Selwyn College, to which he felt he owed a debt when an undergraduate there, and to which he gave much during a long life. What changed his direction was the Second World War. In RAF Intelligence they discovered him to have an eye like a hawk's and to be a genius at the interpretation of photographs. They could show him a burnt scrap of a photograph with streets below and he could tell quicker than anyone where the streets were and what the scrap meant. This gave him experience of the cameras in fighting aircraft, with roll pictures by remote control, which produced photographs in numbers such as no one had seen before. He realised the possibilities for scientific study which this opened up.

On return to Cambridge in 1945, still as a lecturer in geology, St Joseph started to persuade the university to create a department of aerial photography. Prising money out of a university for a wholly new discipline is usually thought to be impossible because it means taking cash away from what exists. Outwardly St Joseph was not a persuasive person - he had no use for the diplomat's arts, he never showed emotion. But what he had was an unassuming and quiet persistence, a total belief in his cause and its future, and the backing of a few great scholars. The RAF helped by winking and pretending that this work would be done on their routine flights so that the university did not need to pay for the petrol or the aircraft. Later the RAF woke up to the need for economy but by that time the university was convinced of the discoveries that were happening.

Hence came a tiny room housing photographs and St Joseph as curator; then a children's cricket pavilion, now with him as director; then a large private house; and finally a distinguished part of the historic Mond laboratory with him as professor, housing what built up into one of the greatest collection of air photographs in the world.

The result was knowledge of the original shaping of old towns or monasteries, detection of soil erosion and plant disease, and help to the policy of preserving rural Britain. But the biggest advance was in Roman archaeology. St Joseph's work provided massive new knowledge of Roman Britain, especially in Scotland. Many new forts (more than 200) were located and some promising excavations begun. Every summer he went to excavate the camp at Inchtuthill. He proved that the Roman general Agricola's raid into Scotland (about 80 AD) went far further north than anyone thought and believed he had located the site of the battle of Mons Graupius near Aberdeen. St Joseph also worked over Denmark and Holland, then above northern France, and in the last years on Roman South-west Germany and over Hungary. It was not easy to get leave to fly over other countries because of the fears of their armies. He published much but left much more unpublished. Luckily for us he collected able successors.

St Joseph needed three different workrooms inside his house for the diverse researches. The work could not be done only by a photographer. It needed the highest scholarship and brilliant perception; you had to know a vast amount before you could understand what the photograph could tell you; you had to own the discrimination to know where to look; and St Joseph was blessed in that he was the person in the field with a professional knowledge of geology. He was also indefatigable. He would go on and on, 20 or 30 times over the same ground, until it yielded its secret. He had hunches which were usually proved right.

He was much consulted by the government commissions or ministries concerned with historical monuments, and forestry, and the environment and conservancy, and agriculture and soil science.

Kenneth St Joseph was precise; had a passion for accuracy; was quiet and unpretentious; held strong principles which were never paraded; was a loyal and unobtrusive Anglican; and had a very happy marriage and family. Dedication never made him cold. He was a warm friend.

(Photographs omitted)