Jerusalem (Mount of Olives) - Eleona

Paragraph: 
III, 41-43
Translation: 

41. (1) (Constantine) took in hand here other sites venerated for their two mystic caves, and he adorned these also with rich artwork. On the cave of the first divine manifestation of the Saviour, where he submitted to the experience of birth in the flesh, he bestowed appropriate honours; while at the other he dignified the monument on the mountain-top to his ascension into heaven. (2) These also he artistically honoured, perpetuating the memory of his own mother, who had bestowed so much good on human life.

...

43. (1) (Helena, mother of Constantine) immediately consecrated to the God she adored two shrines, one by the cave of his birth, the other on the mountain of the ascension. For the God with us allowed himself to suffer even birth for our sake, and the place of his birth in the flesh was announced among the Hebrews by the name of Bethlehem. - - - (3) Again the Emperor's mother erected on the Mount of Olives the monument to the journey into heaven of the Saviour of the Universe in lofty buildings; up by the ridges at the peak of the whole mountain she raised the sacred house of the church, and constructed just there a shrine for prayer to the Saviour who chose to spend his time on that spot, since just there a true report maintains that in that cave the Saviour of the Universe initiated the members of his guild in ineffable mysteries. (4) There also the Emperor bestowed all kinds of offerings and ornaments on the great King.

(transl. Cameron and Hall)

Bibliografical ref.: 
Summary: 
Constantine and his mother Helena order the building of a church in a mystic cave on Mount Olivet, AD 327/8.
Commentary: 

Most scholars identify this church with the basilica of the Eleona built over the cave where Jesus thought his disciples, not with the church built over the hillock of the Ascension. See most recently Shalev-Hurvitz for a full discussion of the literaray sources, with further bibliography.