In 1903, Stephen along with Rev. Raymond Orpen, founded the Guild of Witness (later called the Irish Guild of Witness), to promote the Irish dimension of the Church of Ireland and in 1918 created the Irish Guild of Witness Library[5] In 1921 Stephen moved to Dublin, living in Ardfeenish, 21 Mount Street, bringing with her books from the Irish Guild of Witness, it became the Ardfeenish Library.
In 1931, she donated some 5,000 books on the Bible and theology, from the Irish Guild of Witness, to the church, and in 1932, the Representative Church Body (RCB) Library was established in St. Stpehen's Green, Dublin.[6] She later added some 10000 volumes from her father Sir James Fitzjames Stephen and her grandfather Sir James Stephen a former professor of modern history at Cambridge.
In 1969, the Library was moved to the site of the Divinity Hostel (now the Church of Ireland Theological Institute) in Churchtown. Over the years the RCB Library became the central repository for local (parish) and national Church of Ireland documents.[7]