The Gamble Library was established by donation in 1873, prior to 1873 there was a core library collection at the College. The stock in the core library collection came from the Synod of Ulster and the Secession Synod which united in 1840 to form the Presbyterian Church in Ireland. Union Theolocial College is a union of two nineteenth century Irish Presbyterian theological colleges - The Presbyterian College, Belfast (founded 1853) and Magee Theological College, Londonderry (founded 1865). For many years The Presbyterian College, Belfast was known affectionately as "Assembly's" being the College of the General Assembly of The Presbyterian Church in Ireland. Magee Theological College began as the Theological Department of a College of Arts and Divinity which opened in Londonderry in 1865, and later became Magee University College. When the Arts side was incorporated into the New University of Ulster in 1971, the Theological College was transferred to Belfast, where it was united with the Presbyterian College to form the Union Theological College in 1978. The Gamble Library comprises the stock of all these amalgamated institutions. The subject bias of the Library is theological in nature reflecting the needs and interests of Union Theological College to date.