He was born in 1918, near Swindon, and educated at Rendcomb College in Gloucestershire. Although he read biology at Bristol University, as the first recipient of the Dulverton Open Scholarship, he decided that the study of Chinese culture was to be his vocation. At 16 he had seen the great International Exhibition of Chinese Art, held at Burlington House, London, in 1935-36, an experience he later described as "a turning-point of my life". During the Second World War he studied Chinese art at the Courtauld Institute of Art, in London, and took an MA under Professor K. de B. Codrington at London University in 1946. In 1950 he completed an Honours degree in Classical Chinese at Oxford.
Willetts published his influential two-volume Chinese Art in 1958 with Penguin Books and on the strength of the royalties sailed for China. En route his ship called at Madras and Willetts, engaged by the extraordinary strength of south Indian culture, decided to take a closer look. He stayed six years. A series of scholarly articles on Indian temple arts and China's maritime links with southern India was the result.
1963 saw a new chapter open in Willetts's life. He was invited by the Chancellor of the University of Malaya to become the founding curator of the University Art Museum, Singapore. With his combination of connoisseurship and acumen he built an important collection of Chinese and South-East Asian art, appropriate to the aspirations of the newly emerging independent nations of the region. Of equally lasting importance was the creation of the South-East Asian Ceramic Society which Willetts, as founding president, launched in 1971 with an inaugural exhibition at the University Art Museum.
This exhibition was the first presentation of the then little-known ceramic traditions of Thailand, Cambodia and Vietnam and caused a stir amongst the oriental ceramic cognoscenti. His pioneering catalogue Ceramic Art of South-East Asia inspired a generation of younger scholars and stimulated the interest of government archaeological departments throughout South- East Asia. In the UK, however, his catalogue was reviewed with reluctant praise, and Willetts's contributions patronisingly dismissed by those who failed fully to grasp the significance of these developments for ceramic art history.
Willetts's pursuit of a somewhat rakish life style (which he later described as "reading, thinking and drinking") offended some sensibilities. In 1972 he was invited to be founding curator at the University of Malaya, in Kuala Lumpur. Over the next decade he created the Museum Seni Asia, from which he retired in 1982. He remained in Kuala Lumpur, where he served as chairman of the South-East Asian Ceramic Society West Malaysian Chapter. He organised exhibitions and lectured throughout South-East Asia to the ceramic societies which had subsequently emerged in Jakarta, Manila and Hong Kong, inspired by the example of the Singapore ceramic society. His last important publication, Chinese Calligraphy (1981), signalled a desire to return to his study of Chinese aesthetics.
Willetts never got to China, but it has to be said that the unquestionable loss to Chinese art history was a gain for South-East Asian studies. His contribution went beyond his academic publications: he gave direction to collectors through his connoisseurship and led by example in the formation of important public collections in Singapore and Kuala Lumpur. The establishment of South-East Asian ceramics as a respectable field of inquiry was perhaps his most lasting legacy.
William Willetts, art historian and museum curator: born Purton Stoke, Wiltshire 1918; died Kuala Lumpur 30 January 1995.