The Midnight service is standard on weekdays. It is the first office of the Horologion, and it is celebrated in the middle of the night, before daybreak. In the writing of St John Cassian and the life of St Paul the Simple from Palladius letter to Lausus, we learn the Desert Fathers in Egypt used initially a nocturnal psalmody of 12 psalms. The Sunday midnight office appears only later, beginning in the 15th century and consisting the Canon of the Lifegiving Trinity, in the tone of Octoechos. Beginning on September 22 until Palm Sunday there’s an additional prayer of St Basil the Great. The dismissal and conclusion is similar with that of the office of Compline because in the practice of the Desert Fathers in Egypt and Palestine monastics begin and end their day by seeking mutual pardon at the time of midnight.