The Conferences Of John Cassian by John Cassian
Chapter XI. An inquiry why in Egypt they do not fast during all the fifty days (of Easter) nor bend their knees in prayer.
But it is now time to follow out the plan of the promised discourse. So then when Abbot Theonas had come to visit us in our cell during Eastertide after Evensong was over we sat for a little while on the ground and began diligently to consider why they were so very careful that no one should during the whole fifty days either bend his knees in prayer or venture to fast till the ninth hour, and we made our inquiry the more earnestly because we had never seen this custom so carefully observed in the monasteries of Syria.