The apocryphal Acts of John (C3 AD) attests the existence of a particular cave on the Mount of Olives associated with the teaching of Jesus. According to Eusebius, Constantine’s building programme in Palestine focused on the three caves linked to the key mysteries of the faith, the birth cave in Bethlehem, the rock-cut tomb near Golgotha, and the cave on the Mount of Olives with which the Ascension was also linked. The church built over this cave, under the direction of Queen Helena, was seen by the Bordeaux pilgrim in 333. Egeria (384) is the first to record what became the common name, ‘Eleona’ (Jerusalemites attached an Aramaic a to the Greek elaion, meaning ‘of olives’). After the site for the commemoration of the Ascension had been removed further up the hill, the cave was exclusively associated with the teaching of Jesus on the ultimate conflict of good and evil (Matt.24:1-26: 2- the gospel Egeria heard read in the cave on Tuesday of Holy Week.
Despite the destruction of the church by the Persians in 614, the memory of Jesus’ teaching remained, but there was a significant shift in its content. It tended to become the place where he taught the disciples the Our Father; the basis being a sophisticated harmonization of Luke 10:38- 11:4 with Mark 11:12-25. This was the dominant tradition when the Crusaders constructed an oratory in the ruins (1106). In 1102 a pilgrim heard a story of a marble plaque with the Lord’s Prayer inscribed in Hebrew; another saw one in Greek placed beneath the altar (1170); an inscribed Latin version was found in the excavations.
This tradition has been revived in the decoration of the cloister erected after the Byzantine foundations were brought to light in 1910; tiled panels give the Lord’s Prayer in sixty-two languages.
Source: The Holy Land by Jerome Murphy-O’Connor