The celebration of Christ's ascension into heaven forty days after His Resurrection, witnessed by the Apostles. This moveable feast always falls on a Thursday and marks Christ's return to the Father and His promise to send the Holy Spirit. The feast emphasizes both Christ's divine nature and His continued presence with the Church.

The first Christian Emperor Constantine the Great and his mother, St. Helen, who found the True Cross. Celebrated on May 21st, this feast honors Constantine's legalization of Christianity and Helen's pilgrimage to the Holy Land. Their work established Christianity's place in the Byzantine Empire and preserved many holy sites.

The sacrament of ordination to the threefold ministry of bishop, priest, or deacon. Ordinations take place during the Divine Liturgy, with deacons ordained after the consecration of the gifts, priests after the Great Entrance, and bishops after the Little Entrance. The bishop lays hands on the ordinand while the people sing "Axios!" ("He is worthy!"). Through ordination, the Holy Spirit grants the grace needed for ministry. Only men may be ordained, and bishops must be celibate monastics, while priests and deacons may be married before ordination.

The descent of the Holy Spirit upon the Apostles fifty days after Pascha, marking the birthday of the Church. During Vespers, special kneeling prayers are offered and the church is decorated with greenery. This feast celebrates the completion of Christ's saving work and the beginning of the apostolic mission to all nations.

The day after Pentecost, continuing the celebration of the Holy Spirit's descent upon the Church. Also called 'Trinity Monday,' this feast honors the Third Person of the Trinity specifically. Many Orthodox churches hold special services with kneeling prayers, emphasizing the ongoing work of the Spirit in the Church and in believers' lives.

The Tuesday after Pentecost, continuing the celebration of the Trinity and the gift of the Holy Spirit. This day maintains the festal character of the Pentecost season with special hymns and prayers. Many Orthodox communities hold additional services during Trinity Week to honor the complete revelation of the Triune God.