"...and recited, "He is a priest forever..."

This prayer is a portion of one composed by John D. Sheridan.

Miserichord.

Image found here: http://www.tara.tcd.ie/bitstream/2262/15000/1/ertk0765.jpg

A striking looking miserichord. Remember, this is the underside of the seat. The narrow shelf at top is really the front edge of the seat, unless one lifts the seat up as pictured here. When monks spent long hours standing in prayer and song, the tired among them could rest ever so gently on the shelf without being admonished.

Man mei longe

From the 13th Century. Anonymous. I found it in An English Song Book, edited by Noah Greenburg. A modern translation is also given:

Long may man ween [want] his life to be but oft for him there waits a trick; fair weather often turns to rain, and sunshine is wondrously made. Therefore, man, bethink thyself--all thy green youth shall fade. Well-a-day! there is neither king nor queen who shall not drink the draught of death. Man, ere thou fallest off thy bench, quench thy sin.

Prayer

Lyrics borrowed from the Psalms. Thomas Ravenscroft made it a round for four voices.

http://www.pbm.com/~lindahl/ravenscroft/psalter/r017small.html