50 Days after Easter is the feastday Pentecost (Whitsunday), also called Holy Trinity. The Holy Ghost feastday is on the following day.
Name day of everyone called Trayko, Trayan, Trayana.
It is a church feast that commemorates the Descent of the Holy Ghost upon the Apostles, fifty days after the Resurrection of Christ - on the ancient Jewish festival called the "feast of weeks" or Pentecost. It also has the name of Whitsunday, because of the white garments which were worn by those who were baptised during the vigil; while the name Pentecost ("Pfingsten" in German), comes from the Greek word for "the fiftieth" (i.e. fiftieth day after Easter).
The Feastday of Pentecost occurs 50 days after the celebration of the Glorious Resurrection. It commemorates the descent of the Holy Spirit on the heads of the Apostles, infusing them with the mandate to go forth into the world and preach the Gospel. It is celebrated as a major feastday in all of the ancient Apostolic Churches of East and West, and is considered the birthday of the Church. In the Eastern Orthodox Church, however, the feast does not stand alone.
On Pentecost the Eastern Orthodox Church also celebrates the Feastday of the Holy Trinity and on the Saturday preceding it is "Zadoushnitsa", i.e. one of the five Saturdays throughout the year specially dedicated to the remembrance of the dead.
How and why these three feasts came together at the same time is not known. These three feasts are flexiblei. e. their date is determined by the date of Easter (Resurrection Sunday) which varies from year to year. Fortuitously, rather than by design, the three feasts occur more or less in late spring or early summer, a time when agricultural peoples, are most concerned about preparing the fields and sowing the crops.