St. Justin Martyr

St. Justin was a 2nd century apologist. He defended Christianity to the Roman emperor. His description of the Eucharistic celebration is cited in the Catechism of the Catholic Church, Section 1345:

On the day we call the day of the sun, all who dwell in the city or country gather in the same place. The memoirs of the apostles and the writings of the prophets are read, as much as time permits.
When the reader has finished, he who presides over those gathered admonishes and challenges them to imitate these beautiful things.
Then we all rise together and offer prayers for ourselves . . .and for all others, wherever they may be, so that we may be found righteous by our life and actions, and faithful to the commandments, so as to obtain eternal salvation.
When the prayers are concluded we exchange the kiss.
Then someone brings bread and a cup of water and wine mixed together to him who presides over the brethren.
He takes them and offers praise and glory to the Father of the universe, through the name of the Son and of the Holy Spirit and for a considerable time he gives thanks (in Greek: eucharistian) that we have been judged worthy of these gifts.
When he has concluded the prayers and thanksgivings, all present give voice to an acclamation by saying: ‘Amen.’

St. Justin Martyr, First Apology

St. Justin Martyr is the patron saint of philosophers. His feast day is June 1.

Video: St. Justin Martyr Describes the Early Christian Mass

In this video we see the words of St. Justin wrote to the Roman emperor in 155 AD to defend Christianity. He describes a Mass which would be familiar to us today – the reading from scripture, the homily, the petitions, the offertory, the praying over the gifts, the reception of communion. He even describes bringing communion to those who are not present. He explains that this is called Eucharist and that we believe it is truly the body and blood of Christ. This is a wonderful resource to show the continuity of the order of Mass throughout the ages.