In the traditional Roman Rite this is the feast of St Michael the Archangel. In the Book of Common Prayer it's St Michael and All Angels. The Novus Ordo compromised - more than St Michael but less than All: the Feast of St Michael, St Gabriel, and St Raphael.
O Everlasting God, Who hast ordained and constituted the services of Angels and men in a wonderful order; Mercifully grant that, as Thy holy Angels always do Thee service in heaven, so, by Thy appointment, they may succour and defend us on earth; through Jesus Christ our Lord. Amen.
That's today's collect according to the old BCP. It's the same in the Roman Rite and in the Latin of the Novus Ordo. Even the ICEL stayed pretty close to the ranch on this one.