[citation needed] Besides numerous research papers on the philology of many Celtic languages, he is the author of Medieval Welsh Literature (1997)[6] and The Origins of the "Four Branches of the Mabinogi" (2009).

[citation needed] Breeze has written about Mabinogi studies, and The Mabinogion research, especially addressing historical and political parallels.

Breeze's theory rests on the unusual lack of warlike or fighting heroics compared to preceding literature; the high quantity of material on mothering, besides complex, in-depth portraits of Mabinogi women.

[10] This much has been supported or tolerated by some scholars, but there has been discussion regarding Breeze's preferred candidate Gwenllian ferch Gruffydd.

This work aims to provide a blueprint for locating a range of battles fought during this early period of British history.