Egeria is the most famous of Western pilgrims. She came out of the West (most likely Aquitaine) into the Holy Land between A.D 381 and 384. In this passage from the Itinerarium (the record of her journeys) she describes the pre-dawn liturgy at the Anastasis (a Greek genitive form meaning the ''Resurrection'' - this is the holy Sepulchre, the place from which the Lord came forth on Easter Day - in Egeria's time it was a cave (spelunca) in the rock surrounded by a colonnaded building and flanked by a screen, called the cancellus (which means ''lattice'')).
Here is her description (vulgarisms and Greek forms and all) of the pre-Dawn liturgy (ie: Mattins) at the Anastasis:
Ut autem sciret affectio vestra, quae operatio singulis diebus cotidie in locis sanctis habeatur, certas vos facere debui, sciens, quia libenter haberetis haec cognoscere. Nam singulis diebus ante pullorum cantum aperiuntur omnia hostia Anastasis et descendent omnes monazontes et parthene, ut hic dicunt, et non solum hii, sed et laici preter, viri aut mulieres, qui tamen volunt maturius vigilare. Et ex ea hora usque in luce dicuntur ymni et psalmi responduntur, similiter et antiphonae: et cata singulos ymnos fit oratio. Nam presbyteri bini vel terni, similiter et diacones, singulis diebus vices habent simul cum monazontes, qui cata singulos ymnos vel antiphonas orationes dicunt.
That your kindness may know, how the daily service is held in the holy places, I ought to make you certain, knowing that you would be glad to know these things. For everyday before the song of the cockerals all the doors of the Anastasis are opened and all monks and virgins go down, as they say here, and not these alone, but also lay people, men or women, who wish to keep vigil earlier. And from this hour even unto the dawn hymns are said [she means sung] and psalms are responded, in like manner antiphons also: and after each hymn a prayer is made. For the priests, similarly the deacons, together with the monks, two by two or three by three, take it in turns everyday to say prayers after each of the hymns or antiphons.