During the preparation of the inventory, extensive documentary research was undertaken along with the field survey of a limited number of sites traditionally associated with significant engagements.
Wrth baratoi’r rhestr, ymchwiliwyd yn eang i ddogfennau a chynhaliwyd arolwg maes o nifer gyfyngedig o safleoedd sydd yn ôl traddodiad wedi’u cysylltu â brwydrau arwyddocaol.