Cynidr was a 6th-century Catholic bishop who served the region of Glasbury in Powys. Born in Wales around 501, he was the son of Saint Gwladys and the grandson of King Brychan. As the brother of Saint Eigon, the patron of nearby Llanigon, he belonged to a notable religious lineage. He is primarily recognized as the first bishop of Glasbury and remains a significant figure in Welsh hagiography.