Spofford is generally credited with overseeing the expansion of the Library from a Congressional resource into a national institution. During Spofford's tenure, the Library's collection expanded from over 60,000 items to more than one million. Among his more noted acquisitions was the purchase of a vast collection of early American archives from noted archivist Peter Force. Spofford's hopes were to follow the great library models of Europe, in which "the library would be a comprehensive collection of the literature of the nation." Beginning in the 1830s, the Library of Congress began to receive foreign governmental documents and publications. By the late 1860s, Spofford convinced Congress to allow the Library to become the repository for international documents. Spofford stated that "there is almost no work, within the vast range of literature and science, which may not at some time prove useful to the legislature of a great nation." Spofford's championing of the Copyright Law, passed on July 8, 1870, also expanded the Library's collection through the copyright registration deposit mandate. The law "centralized all U.S. copyright registration and deposit activities at the Library." and stipulated that two copies of every "book pamphlet, map, print, photograph, and piece of music registered for copyright be deposited in the Library." In arguing for the deposit requirement, Spofford suggested that the legislature would "provide a repository of American culture." In his argument for the copyright law to Congress, Spofford wrote that "the Public intelligence and welfare are promoted by every extension of the means of acquiring knowledge." The law established the Library as the de facto national library of the United States and "essentially resolved debate over which institution would serve as America's national library."