The collection, donated in 1902, has been enlarged over the years. It contains more than 20,000 letters varying in date from ca. 1400 to the present, many accompanied by prints and photographs. It includes a set of the Signers of the Declaration of Independence, letters of the Presidents of the United States, Members of the Consitutional Convention of 1787, letters of officers of the American Revolution, as well as a large and valuable collection of letters of distinguished authors, composers, royalty, scientists, educators and businessmen. There are many Quaker letters in this collection.