Oskar Reinhart (1885-1965) was born into an old family of Winterthur merchants. His father, Theodor Reinhart (1849-1919), headed the firm of Volkart Brothers, founded by his wife's family, and pioneered direct trade between India and continental Europe. In a local economy traditionally dominated by the textile industry the firm focused on cotton imports. Aside from his commercial activities, Theodor Reinhart was deeply devoted to art, a love of which he bequeathed to his son. Oskar Reinhart, coming into contact at an early age with the young Swiss and German artists whom his father supported, soon started buying art himself. By the mid-1920s he had acquired the core of his collection. In 1924, at the age of thirty-nine, he was able to realise his dream of withdrawing from the family firm so as to devote himself entirely to expanding his collection.
Also in 1924 Reinhart purchased ʻAm Römerholz̕ , a private residence that formed an excellent home for his collection. He lived in the villa until his death, in 1965, surrounded by his beloved works of art. It was his intention that the collection should ultimately benefit the community. In 1940 he therefore donated his holdings of Austrian, German and Swiss art to the town of Winterthur. That part of the collection has been housed since 1951 in the Museum Oskar Reinhart. In 1958 Reinhart bequeathed the remaining part, together with the ʻAm Römerholz̕ villa, to the Swiss Confederation, which opened it to the public in 1970.