Oliver Brown was the son of Ernest Brown, who had joined Wilfred and Cecil Phillips in 1903 to form Ernest Brown & Phillips, a gallery off Leicester Square. In the first half of the century, the Leicester Galleries, as they were known, became one of the country's leading venues for promoting avant-garde art. Oliver Brown became a partner in 1914 and dedicated his life to the gallery. Cézanne, Van Gogh, Gauguin, Pissarro, Picasso, and Matisse were all given their first one-man shows in Britain at the Leicester Galleries. Kenneth Clark made many purchases there and Brown's experience was valuable to the Arts Council in its early days, as he served on its arts panel from 1949 to 1954. Brian Sewell recalled that ‘Oliver was the prime source of French Impressionists and Post-Impressionists in this country from the very moment the market began to exist. When I went to work at Christie's [in 1958], who was the expert who was called in when any French Impressionist pictures were to be catalogued? It was Oliver, and whatever he said went because we were instructed by Alec [Martin] to accept his opinion’ (quoted in J. Herbert, Inside Christie's, 1990).