The festival of Whitsunday reaches back to the commencement of the Church, although there is no evidence for it, as there is in the case of Easter, it being uncertain whether the passage, 1 Cor. xvi. 8, refers to the Jewish or to the Christian Pentecost. This is not astonishing, for, on the one hand the feast, originally of only one day’s duration, fell on a Sunday, and, on the other, it is so closely bound up with Easter that the one entails the other. That the festival of Whitsunday belongs to Apostolic times is stated in the seventh of the fragments attributed to Irenæus, but these are admitted to be interpolated. In Tertullian, the festival, along with Easter, appears as already well established, so that it must have been in existence for some time. As at Easter, prayer was made standing, and it was the second and last date for the solemn baptism of catechumens.[252] Tertullian, moreover, in accordance with the usage already in use, gives the name of Pentecost, not merely to the day of the festival, but to the whole period from Easter to Whitsunday—a use of the term which appears here and there at a later date,[253] and points out the period as a time of joy.[254] The last day, however, was clearly held in Tertullian’s time to be a festival in an especial sense.[255] Origen and the Canons of Hippolytus make references in passing to the festival of Whitsunday.[256] The Apostolic Constitutions say Whitsunday is to be regarded as a high festival, because on it the Lord Jesus sent down the Holy Ghost.