Unlike more ambitious collectors such as Baron Thyssen-Bornemisza, whose broad range of master-paintings is housed at the imposing Villahermosa Palace in Madrid, Mr Beyeler does not claim to have mounted an exhaustive panorama that takes in every movement in 20th-century art.
During the robber-baron years, when wealthy industrialists and newly minted tycoons avidly acquired Old Master art as signs of status, Americans' appetite for Rembrandts was so keen that attributions were often extremely optimistic.