At Frick's death in 1919, he left his house and all of its contents, including art, furniture, and decorative objects, as a museum to the public. His family continued to live in the house until his wife died. After which the trustees of the collection began the transformation of the house into a museum. The collection opened to the public in 1935.The building itself has been enlarged three times, in 1931–35, 1977 and 2011.