The passage above, taken from the first chapter of the book of Acts in the Christian New Testatment, tells of how, for forty days following Jesus’ crucifixion and death, his disciples were made aware of his continuing presence. These mysterious encounters—culminating in the experience described above, when disciples perceived him ascending into heaven—were the foundation for the belief in resurrection.
It is this final encounter which is remembered on Ascension Day, which occurs forty days after Easter. According to tradition, it was first celebrated in 68 CE, although there is no written evidence of the feast until about 385 CE. One of the six holy days of obligation when mass must be attended, it is celebrated predominantly by Catholics and Anglicans.