The library contained one of the most extensive collections of ancient Welsh manuscripts in history. This included works by Dafydd ap Gwilym, Taliesin, Rhys Goch, Jonas of Menevia, Ederyn the Golden-tongued, Einion the Priest, Cwtta Cyvarwydd, Sion Cent and Dafydd Ddu o Hiraddug amongst others.
It was destroyed and looted by parliamentarian forces under Oliver Cromwell in August 1646, during the English civil war. The destruction of Raglan Library was described as an "irrepairable [sic] loss to the literature of Wales".
- William Beattie (1851). The Castles and Abbeys of England: From the National Records, Early Chronicles, and Other Standard Authors : Illustrated by Upwards of Two Hundred Engravings. Virtue, Spalding. pp. 352–. Retrieved 19 October 2012.
- Iolo Morganwg; J. Williams Ab Ithel; John Williams; John Matthews (2004). The Barddas of Iolo Morganwg: A Collection of Original Documents, Illustrative of the Theology, Wisdom, and Usages of the Bardo-Druidic System of the Isle of Britain. Weiser Books. pp. 7–. ISBN 978-1-57863-307-4. Retrieved 20 October 2012.
- The Four Ancient Books of Wales. Abela Publishing Ltd. January 2011. pp. 20–. ISBN 978-1-907256-92-9. Retrieved 20 October 2012.
- Iolo Morganwg; Owen Jones; Society for the Publication of Ancient Welsh Manuscripts, Abergavenny (1848). Iolo manuscripts: A selection of ancient Welsh manuscripts, in prose and verse, from the collection made by the late Edward Williams, Iolo Morganwg, for the purpose of forming a continuation of the Myfyrian archaiology; and subsequently proposed as materials for a new history of Wales. W. Rees; sold by Longman and co., London. pp. 424–. Retrieved 20 October 2012.
- The Metropolitan. James Cochrane. 1836. pp. 1–. Retrieved 20 October 2012.
- Benjamin Heath Malkin (1807). The scenery, antiquities and biography of South Wales: from materials collected during two excursions in the year 1803. Longman, Hurst, Rees, and Orme. pp. 389–. Retrieved 20 October 2012.
- Lewis Spence (1 March 2004). Mysteries of Celtic Britain. Kessinger Publishing. pp. 100–. ISBN 978-0-7661-8421-3. Retrieved 20 October 2012.
- John R. Kenyon (1 January 2003). Raglan Castle. Cadw Welsh Historic Monuments. ISBN 978-1-85760-169-5. Retrieved 20 October 2012.
- Sharon Turner (1841). The history of the Anglo-Saxons from the earliest period to the Norman conquest. Carey & Hart. pp. 498–. Retrieved 20 October 2012.
- Haneirin Gwawdrydd (1820). The Gododin, and the Odes of the months, tr. by W. Probert. pp. 24–. Retrieved 20 October 2012.