St. Michael himself comes to defend us in battle (Alleluia). He came down from heaven (Ibid.) and appeared in Italy towards 525 under the pontificate of Gelasius I, in Apulia, on the summit of Monte Gargano, near the Adriatic and the ancient Sipontum. He requested that a sanctuary should be erected to him where God should be worshipped, in memory of himself and all the angels, and this place became celebrated on account of numerous miracles.
Benedicite Dominum, omnes Angeli ejus: potentes virtute, qui facitis verbum ejus, ad audiendam vocem sermonem ejus. * Benedic, anima mea, Dominum, et omnia, quae intra me sunt nomini sancto ejus.
Bless the Lord all ye His angels : you that are mighty in strength, and execute His word, hearkening to the voice of His orders. * Bless the Lord, O my soul: and let all that is within me bless His holy name.
(Psalm 102:20,1 from the Introit of Mass)
Deus, qui miro ordine, Angelorum ministeria hominumque dispensas: concede propitius; ut, a quibus tibi mistrantibus in caelo semper assistitur, ab his in terra vita nostra muniatur.
O God, who in a wonderful order hast established the ministry of angels and of men, mercifully grant that even as Thy holy angels ever do Thee service in heaven, so at all times they may defend us on earth.
The Catholic Encyclopaedia on St Michael the Archangel: http://www.newadvent.org/cathen/10275b.htm