The Massachusetts Historical Society is a major research library and manuscript repository. Founded in 1791 by Reverend Jeremy Belknap, a Boston minister, its mission remains constant: to collect, preserve and communicate historical information about Massachusetts and the nation to the widest possible audience. Its holdings encompass millions of rare and unique documents and artefacts vital to the study of American history, many of them irreplaceable national treasures. Examples include correspondence between John and Abigail Adams, the Declaration of Independence and the pen that Abraham Lincoln used to sign the Emancipation Proclamation.