Eastertide is the period of 50 days, spanning from Easter Sunday to Pentecost Sunday. It is celebrated as a single joyful feast, called the "great Lord's Day". Each Sunday of the season is treated as a Sunday of Easter. In some traditions, Easter Sunday is the first Sunday of Eastertide and the following Sunday (Low Sunday) is the second Sunday of Eastertide and so on; in other traditions, following the Sunday of the Resurrection, they are named Second Sunday of Easter, Third Sunday of Easter, etc. up to the Seventh Sunday of Easter, concluding with Pentecost Sunday.