Catechism of the Catholic Church §1291 — excerpt
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…
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.
Also cites: St. Hippolytus, Trad. Ap. 21 SCh 11, 80-95