Winter, who died in December 2014, was best known in recent years as one of the founders of the dealership Trinity Fine Art, which was established in 1984. But prior to that he was a president of Sotheby's Italy and a director of Sotheby's in London.
Italy was always Winter's great love. After graduating from Cambridge he went to Cinecitta in Rome in the hope of becoming a film director. As well as working for Sotheby's Florence, he spent periods living in the city and in nearby Lucca.
Italian works of art feature prominently in the sale on December 10 (with all lots estimated at £3000 or below offered without reserve), be it in the form of Renaissance bronzes, baroque terracotta reliefs, maiolica, Doccia porcelain, or, from the artworks, a group of 28 drawings from the workshop of goldsmith Luigi Valadier.
Most of these come from the album of 144 drawings which Winter discovered, and cover designs for a variety of objects, from inkstands and beakers to finials, table centres, wall sconces and salvers.
"John's breadth of knowledge, from painting and drawing to sculpture, furniture and other decorative arts, above all his beloved Florentine Doccia porcelain, was phenomenal," says Alexander Kader, Sotheby's departmental head of European sculpture and works of art.
It is encapsulated in the 19in (50cm) sculptural white group of Apollo and Daphne from c.1750 based on a model by Massimiliano Soldani-Benzi which was produced from a complex mould of 25 different sections. The estimate is £100,000-125,000.
The collection is consigned by Winter's family. The auction comprises two-thirds of his personal collection and one-third 'stock', though Sotheby's point out that "John was such a personal dealer, he bought everything as if for himself. The collection therefore very much reflects John's personal taste".