CCC 1291
© Libreria Editrice Vaticana Source: vatican.va
A custom of the Roman Church facilitated the development of the Western practice: a double anointing with sacred chrism after Baptism. the first anointing of the neophyte on coming out of the baptismal bath was performed by the priest; it was completed by a second anointing on the forehead of the newly baptized by the bishop. Cf. St. Hippolytus, Trad. Ap. 21 SCh — Sources Chrétiennes (patristic critical-edition series). The first anointing with sacred chrism, by the priest, has remained attached to the baptismal rite; it signifies the participation of the one baptized in the prophetic, priestly, and kingly offices of Christ. If Baptism is conferred on an adult, there is only one post-baptismal anointing, that of Confirmation.
Read the full chapter 1. The Sacraments of Christian Initiation ¶1212–1419