On the 30th of June, the Greek Orthodox Church commemorates the Synaxis (a celebratory gathering) of the Twelve Holy Apostles. The commemoration of a Synaxis is commonly observed on the day following a major feast day.
It recognises the participation of a Saint or a group of Saints in the major feast preceding the Synaxis. For example, the Church holds a Synaxis in honour of St John the Baptist on the day after the Theophany.
The feast of the Synaxis of the Twelve Holy Apostles follows the feast of the pre-eminent apostles Peter and Paul (29 June). Each of the Twelve is honoured on separate dates of the Church calendar. However the Church, in its wisdom, also established a collective commemoration of the Twelve Holy Apostles. This, because the group of Twelve Apostles, fulfilled the Lord’s commission to “Go… make disciples of all the nations, baptising them in the name of the Father and of the Son and of the Holy Spirit” (Mat 28:19).
The names of the Twelve Apostles are: Simon, who was called Peter, and his brother Andrew, the First-called; James the son of Zebedee, and his brother John, who was also the Evangelist and Theologian; Philip, and Bartholomew (see also June 11); Thomas, and Matthew the publican, who was also called Levi and was an Evangelist; James the son of Alphaeus, and Jude (also called Lebbaeus, and surnamed Thaddaeus), the brother of James, the Brother of God; Simon the Cananite (“the Zealot”), and Matthias, who was elected to fill the place of Judas the traitor.