Unlike other denominations, Lutherans celebrate Trinity (Trinity Sunday) in one day with Pentecost, and a week after that.
In the Middle Ages the festivities in honor of the Holy Trinity were made at the local level. Pope Alexander III in the twelfth century, considered it unnecessary and not recommended to comply with the belief that the Holy Trinity is glorified in every service. Pope John XXII in the fourteenth century, decided to observe this holiday in the whole universal Church on the following Sunday after Pentecost.
Now in the Lutheran calendar feast of Pentecost completes the memory of historical figures and events of their lives, and on the feast of the Trinity Church begins six months.