The Catholic Encyclopedia says which books are the Catholic Letters but doesn't say how long ago it was that they were called that. I was wondering, because of another post asking for the oldest instance of the term Catholic. Did St. Jerome or Eusebius ever call them that, was it written in the Codex Vaticanus or the Book of Kells or what?
The word Catholic (katholikos from katholou — throughout the whole, i.e., universal) cf. CATHOLIC ENCYCLOPEDIA: Catholic
The Catholic Letters After the thirteen letters of St. Paul and the letter to the Hebrews come seven other letters (one by St. James, two by St. Peter, three by St. John, and one by St. Jude) which since the time of Origen, Eusebius and St. Jerome have been known as 'catholic' letters, letters to the Church at large, not directed to a particular church or individual: the second and third letters of St. John, even though they are addressed to a private individual are regarded as appendixes to his first letter and are also included in the 'catholic letters' category. cf. A GUIDE TO THE BIBLE | Antonio Fuentes