Sancte Michael Archangele, defende nos in prœlio

On October 13, 1884,  Pope Leo XIII paused at the foot of the altar after Mass, and fell into a sort of coma. When the Pope recovered, he spoke of a terrifying vision he had of the battle between the Church and Satan. Afterwards, Pope Leo went to his office and composed this now famous prayer to St. Michael the Archangel and ordered it to be recited after Low Mass. This was duly done until it was removed after Vatican II.

Sancte Michael Archangele, defende nos in prœlio, contra nequitiam et insidias diaboli esto praesidium. Imperet illi Deus, supplices deprecamur: tuque, Princeps militiae caelestis, Satanam aliosque spiritus malignos, qui ad perditionem animarum pervagantur in mundo, divina virtute, in infernum detrude. Amen.

Carlo Crivelli, National Gallery. 1476. [CC BY 3.0 ].
From an altarpiece which Crivelli painted for a side chapel in the Dominican church at Ascoli Piceno, in the Italian Marche. A framed print is in author's dining room.

Holy Michael the Archangel, defend us in the day of battle; be our safeguard against the wickedness and snares of the devil. May God rebuke him, we humbly pray and do thou, Prince of the Heavenly Host, by the power of God thrust into hell Satan and all the wicked spirits who wander through the world for the ruin of souls. Amen.

 

Totus tuus ego sum

Et omnia mea tua sunt;

Tecum semper tutus sum:

Ad Jesum per Mariam.