In 1534, King Henry VIII—famous today largely for his succession of wives—separated from the Roman Catholic Church and papal rule, creating what is known as the Church of England or the Anglican Church. Though Henry VIII sought reforms, Christianity in England remained relatively Catholic, sparking further divisions within the church and ultimately, the Protestant Reformation. One branch of Protestants, the Puritans—a term that was originally pejorative, painting Puritans as extremists—sought to “purify” the church, advocating for more democratic congregations and an unmediated relationship with God. In the newly formed United States, this gave birth to the Congregational Church.

In the early days of the colonies, the church was not only a place of worship, but also a meetinghouse, a venue for civic business, and an archive. Churches kept records of births, deaths, marriages, baptisms, confessions, excommunications, and council minutes, as well as of issues debated by the democratic congregation, including questions of taxation and representation. The Congregational Library and Archive, taking its name from the Congregationalists, began in 1853 with 56 donated books from the personal collections of Boston clergymen. It was forced to move between rented rooms in the early and mid-1800s, before the present location was completed in 1898. The building, designed to house the growing collection, has a façade featuring four bas reliefs that exemplify Puritan values: religious freedom, equality under the law, education, and philanthropy.

Today, the space is both a library and an archive, containing over 225,000 documents, including church records dating back to the colonial era, the denominational archive of the Congregational Church, accounts of missionary work, theological texts, and nearly 15,000 sermons. One of the rarest items is an original copy of the Cambridge Platform of 1649, the document that outlined the role of the church in colonial New England, addressing issues of doctrine, governance, and Congregational membership. In addition to its theological works, the Congregational Library and Archive can be used for genealogy research and as a window into colonial life.