(I posted this just over a year ago on an Internet forum. It's better that more people see it through this website as well.)
From Psalter of Jesus:
"The Jesus Psalter is believed to have been composed in England by the Brigittine monk, Richard Whitford, who called himself "the Wretch of Sion". This devotion was near and dear to the hearts of English Catholics in the days of persecution. It was printed and sold separately as early as 1520, though no copy from that period is known to have survived. In the oldest manuscripts and books the text of the prayer was usually given in English with the various notes and instructions in Latin."
From The Jesus Psalter, Arranged For Public Recitation By A Monk of Ampleforth Abbey, Carmel of Plymouth, 1995:
"RICHARD WHITFORD (or Whytford) belonged to a family of substance at Whitford in Flintshire. He was a Fellow of Queen's College, Cambridge (The Angel of Syon, p. 34). Afterwards he was received into the family of Richard Foxe, Bishop of Winchester, and by him was made his chaplain during the latter years of Henry VII. While with the bishop he contracted a close friendship with [St.] Thomas More, who sought spiritual counsel at his hands. Later on he determined to leave the world, and restored the Order of St. Bridget in the well-known Monastery of Syon. In his writings he styles himself the 'wretch of Syon.' He lived to see himself turned out of his cell, and the cell itself turned to profane use. On his expulsion he was received into the house of William Blount, Lord Mountjoy, who was extremely charitable to those who suffered for the Faith. The time of his death is not known, but he certainly lived until the accession of Queen Mary, and during the intervening years occupied himself in writing books, as if he were still in his peaceful cell. The Salter of Jesus (in Latin and English) is one of his later writings: it was widely spread among the Catholics of England in the days of persecution, and was a favourite daily devotion with many of them."
A Primer on the Psalter of Jesus:
The Psalter of Jesus gets its name from from the number of times the Holy Name of Jesus is said when it is prayed. It is said at least 10 times with each of the 15 petitions, bringing the total number over 150 (there are 150 Psalms in the Books of Psalms). I can personally attest that this prayer, due to the number of times the Holy Name is said, and the humility of the petitions, is a very powerful one. I learned about it from an English priest who offered Mass on the Feast of the Holy Name in 2004, and gave a homily which mentioned the Psalter of Jesus.
The Psalter of Jesus is divided into three parts; each consisting of five Petitions. Each part is preceded by the reading of Phil. 2: 10, 11. (In the online edition, the following version of the reading is used: "At the Name of Jesus let every knee bow, of things in heaven, of things on earth, and of things in hell; and let every tongue confess that our Lord Jesus Christ is in the glory of God the Father.")
Each of the petitions is concluded by the following prayers:
Have mercy on all sinners, Jesus, I beseech Thee; turn their vices into virtues, and, making them true observers of Thy law, and sincere lovers of Thee, bring them to bliss in everlasting glory.
Have mercy also on the souls in purgatory, for Thy bitter Passion, I beseech Thee, and for Thy glorious Name Jesus.
O Blessed Trinity, one Eternal God, have mercy on me.
The Our Father and Hail Mary is then said (I say them in Latin).
At the end of each part, the following prayers are said before the Our Father and Hail Mary, and the Apostles' Creed is said after them:
Our Lord Jesus Christ humbled Himself, becoming obedient unto death. Even to the death of the Cross.
Hear these my petitions, O my most merciful Saviour, and grant me grace so frequently to repeat and consider them, that they may prove easy steps, whereby my soul may ascend to the knowledge, love, and performance of my duty to Thee and my neighbour, through the whole course of my life. Amen.
The Fifteen Petitions of the Jesus Psalter
First Petition: Jesus, have mercy on me.
Second Petition: Jesus, help me.
Third Petition: Jesus, strengthen me.
Fourth Petition: Jesus, comfort me.
Fifth Petition: Jesus, make me constant.
Sixth Petition: Jesus, enlighten me with spiritual wisdom.
Seventh Petition: Jesus, grant me grace to fear Thee.
Eighth Petition: Jesus, grant me grace to love Thee.
Ninth Petition: Jesus, grant me grace to remember my death.
Tenth Petition: Jesus, send me here my purgatory.
Eleventh Petition: Jesus, grant me grace to avoid bad company.
Twelfth Petition: Jesus, grant me grace to call on Thee for help.
Thirteenth Petition: Jesus, make me persevere in virtue.
Fourteenth Petition: Jesus, grant me grace to fix my mind on Thee.
Fifteenth Petition: Jesus, give me grace to order my life towards mine eternal welfare.