Gwilym practised as a Solicitor in north Wales for 30 years, specialising in property litigation, before being appointed a Lecturer in Law at Bangor University in 2011. He attained his PhD by publication in 2017 and teaches modules on land law, equity and trusts.
Gwilym’s research in Welsh legal history includes a focus on the coexistence and interplay of Welsh and English law in late-medieval and Tudor Wales.
Over many years, and through several publications, he has used estate records as a lens for providing new insights into changing legal practices in Wales across the period c.1400-1600. His research shows a blending of native Welsh land law (derived from Cyfraith Hywel), with English common law, indicating that the gentry of late-medieval and Tudor north Wales moved in a legal environment where the principles of Welsh land law, based on the operation of cyfran and gwelyau for example, existed side-by-side with forms of English common law pertaining to land tenure, settlement and inheritance – even after the Act of Union legislation.
Working closely with archivist Peter Foden, Gwilym has undertaken a detailed analysis of settlement practices and inheritance disputes on the Penrhyn estate, published by the Welsh Legal History Society as At Variance: The Penrhyn Entail.
Gwilym is a Fellow of the Royal Historical Society and member of the Welsh Legal History Society, Legal Wales, European Society for the History of Law and European Society for Comparative Legal History. He is copy editor for the European-based journal Comparative Legal History. Between 2017-23 he served as Undersheriff of Gwynedd.