The Synaxis of the Glorious and All-Praiseworthy Twelve Apostles of Christ appears to be an ancient Feast. The Church honors each of the Twelve Apostles on separate dates during the year, and has established a general commemoration for all of them on the day after the commemoration of the Glorious and First-Ranked among the Apostles Peter and Paul.
The holy God-crowned Emperor Constantine the Great (May 21) built a church in Constantinople in honor of the Twelve Apostles. There are instructions for celebrating this Feast which date from the fourth century.
For lists of the Apostles' names, see: Mt.10:2, Mark 3:14, Luke 6:12, Acts 1:13, 26.
Troparion - Tone 4
First-enthroned of the apostles,
teachers of the universe:
Entreat the Master of all
to grant peace to the world,
and to our souls great mercy!
Kontakion - Tone 2
Podoben: “Seeking the highest...”
Today Christ the Rock glorifies with highest honor
Peter, the rock of faith and leader of the apostles,
together with Paul and the company of the twelve,
whose memory we celebrate with eagerness of faith,
giving glory to the One Who gave glory to them.