Highlights of the collection include:
- a late 14th century version of Giraldus Cambrensis’ Itinerarium Cambriae and Descriptio Cambriae (NLW MS 3024C)
- the so-called Mostyn Medical Manuscript (or ‘Mostyn 88’), written by Gutun Owain circa 1487-9 (NLW MS 3026C)
- the second part of the Chronicle of Elis Gruffudd, ‘soldier of Calais’, covering the period 1066-1552 (NLW MS 3054D)
- Wiliam Cynwal’s Pedigree Book, written by the poet and herald between 1565 and 1585 (NLW MS 21249B)
- John Jones of Gellilyfdy’s great collection of Welsh englynion, written at various times between 1605 and 1618 (NLW MS 3039B).