It appears that the apostle had two names, each existing in a double form - Greek and Hebrew, Symeon (iivr,w) which was Graecized according to the sound into Simon, and Cephas (s;') which was Graecized according to the meaning into Peter (Mrpos).
Symeon and Simon are both well-known names in Aramaic and Greek respectively, but Cephas and Peter are previously unknown.
The Gospels agree in regarding Cephas or Peter as an additional name, which was given by Christ.