Deus Propicius Esto (God be favorable to me, a sinner)
deus propicius esto ("God be favorable to me")
A prayer from medieval psalters, possibly with origins in Saint Augustine, as reproduced in (and/or translated by) "The Stripping of the Altars: Traditional Religion in England, 1400-1580"] by Eamon Duffy (pp 269-270). Duffy reproduced the prayer in the context of medieval seriousness about what the prayer calls, "the dreadful judgment."
A Latin version follows below, with a slightly different text, as reproduced from from Folio 15r, The Burnet Psalter. University of Aberdeen
Deus Propicius Esto ("God be favorable to me")
God be favorable to me, a sinner,
and be my guard all the days of my life.
God of Abraham, God of Isaac, God of Jacob,
have mercy on me, and send to my aid Michael your Archangel,
that he may keep, protect and defend me
from all my enemies, visible and invisible.
Holy Michael, the Archangel of God, defend me in battle,
that I may not perish in the dreadful judgment.
Archangel of Christ, by the grace which you have merited
I beseech you, through Our Only-Begotten Lord Jesus Christ,
draw me today and always from deadly peril.
Holy Michael, Holy Gabriel, Holy Raphael,
all holy angels and archangels of God, hasten to help me.
I beseech you all, you heavenly Virtues,
that by the power of the most high God you give me your aid,
so that no enemy may be able to condemn or oppress me,
neither in my house, nor out of it,
neither sleeping nor walking.
Behold + the cross of the Lord, begone your enemies.
The lion of the tribe of Judah has conquered;
Root of David, stem of Jesse, savior of the world,
who have redeemed me through your cross and blood,
save me, help me, my God.
Agios, Agios, Agios.
Cross of Christ, protect me.
Cross of Christ, save me.
Cross of Christ, defend me from every evil.
Deus Propicius Esto
Deus propicius esto michi peccatori
et sis custos mei omnibus
diebus vite mee.
Deus Abraham deus Ysaac, deus Iacob
miserere mei et mitte in adiutorium
meum Michaelem archangelum
qui me protegat et defendat ab omnibus
inimicis meis visibilibus et invisibilibus.
Sancte Michael archangele
defende me in prelio
ut non peream in tremendo iudicio.
Archangele Christi Michael
per graciam quam meruisti
te deprecor per dominum
nostrum Ihesum Christum
unigenitum filium dei ut eripias
me hodie et in omni tempore
ab omnibus periculis