Background
Trapp was born in Carterton, New Zealand, on 16 July 1925, and was educated at Dannevirke School.
Trapp was born in Carterton, New Zealand, on 16 July 1925, and was educated at Dannevirke School.
He graduated Master of Arts from Victoria University College in Wellington, New Zealand in 1947, and began his career as an academic at that institution in 1950, after a spell working at the Alexander Turnbull Library from 1946 to 1950.
In 1951 he emigrated to the United Kingdom, where he worked first at Reading University and from 1953 at the Warburg Institute, London University. At the Warburg he was assistant librarian (1953-1966) and librarian (1966-1976), before succeeding Ernst Gombrich as director (1976-1990). He died in London on 14 July 2005.
Trapp became a Fellow of the Society of Antiquaries in 1978 and a Fellow of the British Academy in 1980. In 1990, on his retirement from the Directorship of the Warburg Institute he was presented with a Festschrift in his honour. In the same year he was awarded the Commander of the Order of the British Empire.