The collection started in the 1920s as a private collection by Heinrich, Baron Thyssen-Bornemisza de Kászon. In a reversal of the movement of European paintings to the United States during this period, one of the elder Baron's sources was the collections of American millionaires coping with the Great Depression and inheritance taxes, from which he acquired such exquisite old master paintings as Ghirlandaio's portrait of Giovanna Tornabuoni (once in the Morgan Library) and Carpaccio's Knight (from the collection of Otto Kahn).[1] The collection was later expanded by Heinrich's son Baron Hans Heinrich Thyssen-Bornemisza (1921–2002),[2] who assembled most of the works from his relatives' collections and proceeded to acquire large numbers of new works to produce what is one of the world's finest private art collections.
The collection was initially housed in the family estate in Lugano in a twenty-rooms building modelled after the Neue Pinakothek in Munich. In 1988 the Baron filed a request for building a further extension designed by British architects James Stirling e Michael Wilford but the plan was rejected by the Lugano City Council.
In 1985, the Baron married Carmen "Tita" Cervera (a former Miss Spain 1961) and introduced her to art collecting. Cervera's influence was decisive in persuading the Baron to relocate the core of his collection to Spain where the local government had a building available just next to the Prado. The Thyssen-Bornemisza Museum officially opened in 1992 showing 715 works of art. A year later, the Spanish Government bought this collection outright.
The Baroness remains involved with the museum. She personally decided the salmon pink tone of the interior walls and in May 2006 publicly demonstrated against plans of the Mayor of Madrid, Alberto Ruiz-Gallardón to redevelop the Paseo del Prado as she thought the works and traffic would damage the collection and the museum's appearance.