The Synaxis of the Leader of the Heavenly Hosts Michael, and the Other Heavenly Bodiless Hosts was established at the beginning of the IV Century at the local Laodician Council, which occurred several years before the First Ecumenical Council. The Laodician Council by its 35th Canon condemned and renounced as heretical the worship of angels as creators and rulers of the world and it affirmed their proper Orthodox veneration. A feastday was established in November -- the ninth month from March (with which month the year began in ancient times) -- in accordance with the 9 Ranks of Angels. The eighth day of the month was decreed for the intended Assemblage of all the Heavenly Powers -- in conjunction with the Day of the Dread Last-Judgement of God, which the holy fathers called the "Eighth Day" -- since after this age in which the seven days [of Creation] have elapsed will come the "Eighth Day" -- and then "shalt come the Son of Man in His Glory and all the holy Angels together with Him" (Mt 25:31).
The Angelic Ranks are divided into three Hierarchies: highest, middle, and lowest. In the Highest Hierarchy are included the three Ranks: the Seraphim, Cherubim and Thrones. Closest of all to the MostHoly Trinity stand the six-winged Seraphim (Flaming, and Fiery) (Is 6:12). They blaze with love for God and impel others to it.
After the Seraphim there stand before the Lord the many-eyed Cherubim (Gen 3:24). Their name means: outpouring of wisdom, enlightenment, since through them -- radiating with the light of Divine-knowledge and understanding of the mysteries of God, there is sent down wisdom and enlightenment for true Divine-knowledge.
After the Cherubim, stand God-bearing through grace given them for their service, the Thrones (Col 1:16), mysteriously and incomprehensibly upholding God. They serve the uprightness of God's justice.
The Middle Angelic Hierarchy consists of three Ranks: Dominions, Powers, and Authorities:
(Col 1:16) hold dominion over the successive ranks of Angels. They instruct the earthly authorities, established from God, to wise governance. The Dominions influence rule by miracles, they quell sinful impulses, subordinate the flesh to the spirit, and provide mastery over the will to conquer temptation.
(1 Pet 3:22) fulfill the will of God. They work the miracles and send down the grace of wonderworking and perspicacity to saints pleasing to God. The Powers give assist to people in bearing obediences, encourage them in patience, and give them spiritual strength and fortitude.
(1 Pet 3:22, Col 1:16) have authority to quell the power of the devil. They repel from people demonic temptations, uphold ascetics and guard them, helping people in the struggle with evil ponderings.
In the Lowest Hierarchy are included the three Ranks: Principalities, Archangels, and Angels:
(Col 1:16) have command over the lower angels, instructing them in the fulfilling of Divine commands. To them are entrusted to direct the universe, and protect lands, nations and peoples. Principalities instruct people to render honour to everyone, as becomes their station. They teach those in authority to fulfill their necessary obligations, not for personal glory and gain, but out of respect for God and benefit for neighbour.
(1 Thess 4:16) announce about the great and most holy, they reveal the mysteries of the faith, prophecy and understanding of the will of God, they intensify deep faith in people, enlightening their minds with the light of the Holy Gospel.
(1 Pet 3:22) are closest to all to people. They proclaim the intent of God, guiding people to virtuous and holy life. They protect believers restraining them from falling, and they raise up the fallen; never do they abandon us and always they are prepared to help us, if we so desire.
All the Ranks of the Heavenly Powers have in common the name Angels -- by virtue of their service. The Lord reveals His will to the highest of the Angels, and they in turn inform the others.
Over all the Nine Ranks, the Lord put the Holy Leader Michael (his name in translation from the Hebrew means "who is like unto God") -- a faithful servitor of God, wherein he hurled down from Heaven the arrogantly proud day-star Lucifer together with the other fallen spirits. And to the remaining Angelic powers he cried out: "Let us attend! Let us stand aright before our Creator and not ponder that which is displeasing unto God!" According to Church tradition, in the church service to the Archistrategos Michael concerning him, he participated in many other Old Testament events. During the time of the Exodus of the Israelites from Egypt he went before them in the form of a pillar of cloud by day and a pillar of fire by night. Through him the power of the Lord was made manifest, annihilating the Egyptians and Pharaoh who were in pursuit of the Israelites. The Archangel Michael defended Israel in all its misfortunes.
He appeared to Jesus Son of Joshua and revealed the will of the Lord at the taking of Jericho (Josh 5:13-16). The power of the great Archistrategos of God was manifest in the annihilation of the 185 thousand soldiers of the Assyrian emperor Sennacherib (4  Kings 19:35); also in the smiting of the impious leader Antiochos Illiodoros; and in the protecting from fire of the Three Holy Youths -- Ananias, Azarias and Misail, thrown into the fiery furnace for their refusal to worship an idol (Dan 3:22-25).
Through the will of God, the Archistrategos Michael transported the Prophet Avvakum (Habbakuk) from Judea to Babylon, so as to give food to Daniel, locked up in a lions' den (Kondakion of Akathist, 8).
The Archangel Michael prevented the devil from displaying the body of the holy Prophet Moses to the Jews for idolisation (Jude 1:9).
The holy Archangel Michael showed his power when he miraculously saved a lad, cast by robbers into the sea with a stone about his neck at the shores of Athos [Athos Paterikon].
From ancient times the Archangel Michael was famed by his miracles in Rus'[Russia]. In the Volokolamsk Paterikon there is included a narrative of the Monk Paphnutii of Borovsk with an account of Tatar "baskaki" [tax-gatherers] concerning the miraculous saving of Novgorod the Great: "And wherefore Great Novgorod never was taken by the Hagarites ... when by the sufferance of God for our sins the godless Hagarite emperor Batu devoured and set aflame the Russian land and was come to the New City (i.e. Novgorod) and God and the MostHoly Mother of God shielded it with an appearance of Michael the Archistrategos, which did forbid him to enter into it. He [Batu] was come to the Lithuanian city and did come towards Kiev and did see the stone church over the doors of which the great Archangel Michael had written and spoken unto the prince his allotted fate: 'By this we have forbidden entry into Great Novgorod'."
Intercession for Russian cities by the MostHoly Queen of Heaven always involved Her appearances with the Heavenly Hosts, under the leadership of the Archistategos. Grateful Rus' acclaimed the Most Pure Mother of God and the Archangel Michael in church singing. To the Archistrategos Michael are dedicated many a monastery, cathedrals, court and merchant churches. In old Kiev at the time of the accepting of Christianity, there was erected a cathedral of the Archangel, and a monastery also was built in his name. Archangel cathedrals stand at Smolensk, Nizhni Novgorod, Staritsa, a monastery at Great Ustiug (beginning XIII Century), and a cathedral at Sviyazhsk. In Rus' there was not a city, wherein was not a church or chapel, dedicated to the Archangel Michael. One of the chief temples of the city of Moscow -- the burial church in the Kremlin -- is dedicated to him. Numerous and beautiful icons of the Chief-in-Rank of the Highest Powers are also in his Cathedral. One of these -- the Icon "Blest Soldiery" --written in the Uspenie [Dormition] Cathedral of the Moscow Kremlin, where the saintly soldiers -- Russian princes -- are depicted under the leadership of the Archistrategos Michael.
From Sacred Scripture and Sacred Tradition are likewise known the Archangels:
-- strength (power) of God, herald and servitor of Divine almightiness (Dan 8:16, Lk 1:26)
-- the healing of God, the curer of human infirmities (Tobit 3:16, 12:15)
-- the fire or light of God, enlightener (3 Ezdras 5:20)
-- the prayer of God, impelling to prayer (3 Ezdras 5:16)
-- the glorifying of God, encouraging exertion for the glory of the Lord and interceding about the reward of efforts
-- distributor of the blessing of God for good deeds, entreating the mercy of God for people
-- the raising up to God (3 Ezdras 4:36)
On icons the Archangels are depicted in accord with the trait of their service:
-- tramples the devil underfoot, and in his left hand holds a green date-tree branch, and in his right hand a spear with a white banner (or sometimes a fiery sword), on which is outlined a scarlet cross.
-- with a branch from paradise, presented by him to the MostHoly Virgin, or with a shining lantern in his right hand and with a mirror made of jasper in his left.
-- holds a vessel with healing medications in his left hand, and with his right hand leads Tobias, carrying the fish [for healing -- Tobit 5-8].
-- in raised right hand hold a bare sword at the level of his chest, and in his lowered left hand "a fiery flame."
-- in a prayerful posture, gazing downwards, hands folded to the chest.
-- in his right hand holds a golden crown, in his left a whip of three red (or black) branches.
-- on his garb are a multitude of rose blossoms.
-- holds in his hand balance-scales