Corpus Juris Civilis
Normally, these sponsors were the natural parents of a child, as emphasized in 408 by St. Augustine who suggested that they could, it seems exceptionally, be other individuals. Within a century, the "Corpus Juris Civilis" indicates that parents had been replaced in this role almost completely. This was clarified in 813 when the Synod of Mainz prohibited natural parents from acting as godparents to their own children.