The Serbs were baptized by Constantinopolitan missionaries sent by Basil I, after Mutimir had acknowledged Byzantine suzerainty. Basil may have also sent a bishop. The Christianization was due partly to Byzantine and subsequent Bulgarian influence. It is important to note that at least during the rule of Kotsel of Pannonia (861–874), communications between Serbia and Great Moravia must have been possible. The pope was presumably aware of this fact when planning Methodios' diocese, as well as the fact that the Dalmatian coast was in Byzantine hands as far north as Split. There is a possibility that some Cyrillomethodian pupils reached Serbia in the 870s, perhaps even sent by Methodius himself. Serbia is accounted Christian as of about 870. The lasting Christian identity is evident in the tradition of theophoric names in the next generation of Serb royalty: Petar Gojniković, Stefan Mutimirović and Pavle Branović. "Petros" and "Stephanos" are both characteristically Byzantine.