E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
September 29th, one of the quarter-days when rents are paid, and the day when magistrates are elected. Michael the archangel is represented in the Bible as the general of the celestial host, and as such Milton represents him. September 29th is dedicated to Michael and All Angels, and as magistrates were once considered angels or their representatives, they were chosen on the day of All Angels.
I saw another sign in heaven . . seven angels [magistrates, or executors of Gods judgments], having the seven last plagues . . filled with the wrath of God. (Rev. xv.l.) Those ministers of religion who acted as magistrates were also called angels. There is no power but of God. The powers that be are ordained of God.