Тhe descent of the Holy Ghost - Pentecost - Trinity Sunday
The Feast of Holy Pentecost is celebrated each year on the fiftieth day after the Great and Holy Feast of Pascha (Easter) and ten days after the Feast of the Ascension of Christ. The Feast is always celebrated on a Sunday. The Feast commemorates the descent of the Holy Spirit upon the Apostles on the day of Pentecost, a feast of the Jewish tradition. It also celebrates the establishment of the Church through the preaching of the Apostles and the baptism of the thousands who on that day believed in the Gospel message of salvation through Jesus Christ. The Feast is also seen as the culmination of the revelation of the Holy Trinity.