Forty days after Easter, a Thursday. Most US dioceses keep it on the Sunday after (May 9). The Feast of the Ascension of Jesus Christ (also called the Solemnity of the Ascension of the Lord, Ascension Day, Ascension Thursday; or sometimes Holy Thursday, which can also mean the Thursday before Easter) commemorates the Christian belief of the bodily Ascension of Jesus into Heaven. It is one of the ecumenical (shared by multiple denominations) feasts of Christian churches, ranking with the feasts of the Passion and Pentecost. Following the account of Acts 1:3 that the risen Jesus appeared for 40 days prior to his Ascension, Ascension Day is traditionally celebrated on a Thursday, the fortieth day of Easter according to inclusive counting, although some Christian denominations have moved the observance to the following Sunday, sometimes called Ascension Sunday. The day of observance varies by ecclesiastical province in many Christian denominations, as with Catholics and Lutherans, for example. Ascensiontide refers to the ten-day period between the Feast of the Ascension and the Feast of Pentecost. The Sunday within that period may be referred to as the Seventh Sunday of Easter or the Sunday in Ascensiontide. Wiki link Dates computed from the General Roman Calendar. Text: Wikipedia (CC BY-SA).