We learn still further from the "Ordines Romani" that when the Pope was to pontificate in a designated district all the acolytes of that region went to the Lateran Palace to receive and accompany him. In the sixth or seventh century, perhaps a little earlier, the chief acolyte of the stational church, carrying the sacred chrism covered with a veil, and, directing the procession, preceded on foot the horse on which the Pope rode. The other acolytes followed, carrying the Gospel-book, burses, and other articles used in the holy sacrifice. They accompanied the Pope to the secretarium or sacristy. One of them solemnly placed the book of Gospels upon the altar. They carried seven lighted candles before the pontiff entering the sanctuary." (The Catholic Encyclopedia)
We have mentioned the seven acolytes at papal Mass numerous times before, but I wished to share the photo above (courtesy of Fotagrafia Felici) from this morning's Chrism Mass at St. Peter's, since it shows, better than heretofore I think, the seven acolytes.