In his time, he was known in France as a chronologist. Pezron traced Welsh and Breton origins  to the Celts of ancient writers, and traced the Celts further to eponymous hero-patriarchs from Gaul to Galatia.
In his time, he was recognized as a scholar of chronology. Pezron established connections between the Welsh and Breton peoples and the ancient Celtic writers, and further explored the ancestry of the Celts through legendary figures from Gaul to Galatia.