Dennis King was outstanding in his generation as a restorer of medieval stained glass. He was not only a master of his craft, which was enriched during his lifetime by a wide range of new techniques; he had a rare sensibility to the art of glazing as it was practised in the Middle Ages, and a total dedication to the work of restoration.
He spent his working life in Norwich, of which he was a loyal and active citizen. He was educated at Norwich School, which he left aged 15 to set up in 1927, with his father, a firm later incorporated as G. King and Son (Lead Glaziers) Ltd and established in its own workshops in King's Lane. Such was the growth of its reputation, especially from 1945 onwards, that for decades it was the first resort of those responsible for the maintenance of stained glass not only in East Anglia, but much further afield. Demands outran the capacity of the workshop, but King was reluctant to refuse his help, and would send at once to take out damaged panels and put in temporary replacements. Often enough the panels had then to be stored away until time could be found to repair them and put them back into place.
King & Son worked on many prestigious collections of medieval glass. In 1951, for instance, they tackled the complicated and delicate task of cleaning and restoring the outstanding glass of Winchester College Chapel, which had been widely scattered and much damaged; King later wrote, with John Harvey, a paper for Archaeologia (in 1971) describing the glass and the work he did on it.
In 1957 he restored and re-arranged the gallery of 15th- century figures in Long Melford Church, Suffolk, and in 1967 those at Browne's Hospital, Stamford. In 1962 he worked on the 14th-century glass in Merton College Chapel, Oxford, and throughout the 1960s, 1970s and 1980s maintained and repaired the great windows of King's College Chapel, Cambridge, as well as setting up in many of its side-chapels new arrangements of medieval panels, roundels and fragments.
A strip of glass painted to restore a broken roundel of Tobias and the Fish, for instance, would be distinguishable only by experts from the original; and when a mass of fragments from the original glazing of the Franciscan church at Cambridge was unearthed in Sidney Sussex College he made of them not a series of meaningless mosaics, as his predecessors would no doubt have done, but designs that show off their strikingly rich colours to the full.
Another roundel, in the chapel at King's, illustrates both the traditional method of repair with mending-leads and the new technique of edge-mending with silicon adhesive. It is a rare piece of Burgundian work from the 15th century showing the two cobbler saints Crispin and Crispinian. It arrived at King & Son's workshop in about 1970 in shattered state. At this stage King painted a new glass roundel, filling in the missing parts of the design; he then cut out from his copy the pieces necessary to complete the fragmented original.
When the Glaziers' Trust was set up at York in 1967, and the cathedral workshops at Canterbury, King was inevitably called in as a technical consultant. By the mid-1980s, when he was well into his seventies, a number of other firms had been established, and began to take on work that the Norwich workshop could no longer tackle. However, King continued until the last month of his life as adviser to his son Michael, who succeeded him as head of the firm.
Dennis King was made a Freeman of the City of Norwich as early as 1933, and of the City of London in 1969; he became a Fellow of the Society of Antiquaries in 1959; he was appointed OBE in 1979 for services to the conservation of stained glass. He was a Liveryman of the Worshipful Company of Glaziers and Painters of Glass, a member of the International Technical Committee of the Corpus Vitrearum Medii Aevi (an international record of medieval and later stained glass), and a Founder Trustee of the Ely Stained Glass Museum.