IV. The Liturgical Celebration of the Eucharist

From The Catechism of the Catholic Church

1345
As early as the second century we have the witness of St. Justin Martyr for the
basic lines of the order of the Eucharistic celebration. They have stayed the
same until our own day for all the great liturgical families. St. Justin wrote
to the pagan emperor Antoninus Pius (138-161) around the year 155, explaining
what Christians did:

PART TWO: THE CELEBRATION OF THE CHRISTIAN MYSTERY

SECTION TWO THE SEVEN SACRAMENTS OF THE CHURCH
- CHAPTER ONE THE SACRAMENTS OF CHRISTIAN INITIATION
  - Article 3 THE SACRAMENT OF THE EUCHARIST
    - IV. The Liturgical Celebration of the Eucharist

From The Catechism of the Catholic Church – rosary.team