The spiritual powers of the Sun have always been important to our evolution, according to Steiner.
Foremost are Christ, the Sun God, and Michael, the Sun Archangel.
Michael is a warrior, Christ's champion, Christ's countenance. As such, he is a spiritual being of extreme significance to humanity, comparable to Lucifer and Ahriman, whom he helps subdue. "The third spiritual being important for an understanding of Steiner's teaching on man's place in the cosmos [in addition to Lucifer and Ahriman] is the Archangel Michael ... Rudolf Steiner describes the mission of Michael on behalf of humanity in relation to Ahriman, Lucifer, and Christ: 'Michael-Christ will stand in the future as the guiding word at the entrance to the path upon which man may arrive at his world-goal [i.e., our evolutionary fulfillment]....' The concept of Michael-Christ is a way of expressing 'the most perfect' accord between the Mystery of Golgotha [i.e., the miraculous, redemptive union of god with man] and the Being and Mission of Michael ... 'Michael is already at this time active for humanity from the spiritual world. He is preparing his later work from out of the supersensible. He is giving humanity impulses which preserve the former relation to the Divine-Spiritual world, without this preservation adopting a Luciferific character ... [Man's recent] evolution was guided, through the Michael Mission [i.e., Michael's divine task], into paths which brought the progress of Earth-humanity once more into a good and healthy relation to the spiritual world ... Michael stands in this activity between the Luciferic World-picture and the Ahrimanic World-intellect. The World-picture becomes through him a World-revelation full of wisdom, which reveals the World-intellect as Divine World-activity.'" — Robert A. McDermott quoting Steiner, THE ESSENTIAL STEINER (Lindisfarne Press, 2007), p. 375.
Through Christ, aided by Michael, the dire effects of Lucifer and Ahriman are moderated, becoming beneficial. The "Luciferic World-picture" is the conception of reality produced by Lucifer; the "Ahrimanic World-intellect" is the faulty, intellectual cognitive power that can lead to a wholly material, mechanical world. Michael helps convert these to positive variants: a true, spiritual world conception and a true, clairvoyant power of cognition, the active participation of divinity in our being. Make no mistake, however: Michael is a warrior, and he must fight the powers of darkness before light can prevail. This is clearest in the battles he has repeatedly fought with Ahriman, aka Mammon. Michael has supplanted Gabriel in guiding human affairs, but when Michael arrived so did a "dark god." "[I]n November of the year 1879 there occurred on the astral plane something very similar to a birth ... The rulership of Gabriel was replaced by another archangel, under whose leadership we now stand, the archangel Michael. He is the radiant sun that esoteric wisdom lets shine forth on a small band of people [can you guess who Steiner means?] ... [S]imultaneously with Michael a dark god has entered into his rulership: the god Mammon. For esotericism, Mammon is not only the god of money. He is much more the leader of all vile black powers. And his hordes attack not only human souls, but also the physical bodies of humans in order to gnaw away at them and ruin them. People speak of bacteria a lot more today not because they know more about them, but because bacteria have taken on a very special form today. And in the future they will get the upper hand in a terrifying way. When that black age approaches, then fraternal war will rage in a gruesome way, and poor human bodies will waste away, terribly afflicted by diseases and plagues. The stigma of sin will be impressed on human bodies visible to everyone." — Rudolf Steiner, ESOTERIC LESSONS 1904-1909 (Steiner Books, 2007), pp. 232-233. In case the forgoing left any doubt, here's a clarification on one point: "Mammon, the spirit of hindrances and darkness, has countless helpers who incarnate as bacteria." — Ibid., p. 208.
Here are statements from Steiner’s lecture “The Battle between Michael and ‘The Dragon’” in THE FALL OF THE SPIRITS OF DARKNESS (Rudolf Steiner Press, 2008), pp. 136-148. Michael's battles benefit us — but they also have the unfortunate effect of sending evils down to the plane where we currently dwell: Earth.
“The deeper sources of [Earthly] events... must be sought in the world of the spirit. And if we investigate the processes in that world which have come to outer expression in the event of which I have just spoken, we have to point to a struggle, a real war in that world, which began then and came to a certain conclusion for the world of the spirit by the autumn of 1879. To have the right idea about these things, you must visualize a battle which continued for decades in the spiritual worlds, from the 1840s until the autumn of 1879.
“This may be called a battle which the spirits who are followers of the spirit belonging to the hierarchy of Archangels whom we may call Michael fought with certain ahrimanic powers [minions of Ahriman]. Please consider this battle to have been in the first place a battle in the spiritual world. Everything I am referring to at the moment relates to this battle fought by Michael and his followers against certain ahrimanic powers.”
“To see something like this in the right way, we can always call on an image which humanity has known throughout its evolution — the fight between Michael and the dragon. This image has come up again and again in the course of evolution. We may characterize it by saying that every battle between Michael and the dragon is similar to the one in the 1840s, but it is about different things — harmful and damaging things. We may say that a particular crowd of ahrimanic spirits seek over and over again to bring something into world evolution, but they are always overcome. And so they also lost the battle in the autumn of 1879, and, as I said, this was in the spiritual world.”
“Losing the battle means they [the Ahrimanic powers] are no longer to be found in the heavens, to use the biblical term. Instead they are to be found in the human realms, which means that the late 1870s were a particular time when human souls became subject to ahrimanic powers with regard to certain powers of perception...[that is] the ahrimanic materialistic view with its personal — mark this well — its personal bias ... From the autumn of 1879 onwards, these ahrimanic impulses — powers of perception and of will — became the personal property of human beings. Before this they were more of a general property, now they were transplanted to become personal property. We are thus able to say that due to the presence of these ahrimanic powers from 1879 onwards, personal ambitions and inclinations to interpret the world in materialistic terms came to exist in the human realm. You only have to trace some of the events which have arisen because of personal inclinations since then, to understand that they resulted when the Archangel Michael drove the dragon, that is the crowd of ahrimanic spirits, from the realms of the spirit, from the heavens, down to earth.”
“As already mentioned, these battles have recurred over and over again, but always on different issues. In the distant past, the crowd of ahrimanic spirits were also cast down from the spiritual worlds into the earthly realm when they had lost such a battle. You see, they would return to the attack again and again. After one of these battles, for example, the crowd of ahrimanic spirits populated the earth with the earthly life-forms which the medical profession now calls bacilli. Everything which has the power to act as a bacillus, everything in which bacilli are involved, is the result of crowds of ahrimanic spirits being cast down from heaven to earth at a time when the dragon had been overcome. In the same way the ahrimanic, mephistophelean way of thinking has spread since the late 1870s as the result of such a victory. Thus we are able to say that tubercular and bacillary diseases come from a similar source as the materialism which has taken hold of human minds.”
“The Moon was once part of the Earth; it was cast out from the Earth. As a result, certain Moon influences took effect on Earth, and this, too, followed a victory won by Michael over the dragon. We are therefore also able to say that everything connected with certain effects relating to the phases of the Moon, and all impulses which reach the Earth from the Moon, have their origin in a similar battle between Michael and the dragon.”
“Some individuals develop an irresistible hankering for intellectual materialism which arises from being in league with the fallen Ahriman. They gradually come to love the impulses which Ahriman raises in their souls and, indeed, consider them to be a particularly noble and sublime way of thinking ... Everything which happens within the great scheme of things does also have its good side. It is because the ahrimanic powers entered into us when Michael won his victory that we are gaining in human freedom ... [But] There always is the danger of people continuing in materialism, in the materialistic, ahrimanic way of thinking, and carrying this on into ages when, according to the plan of things, it should have been overcome. The people who do not turn away from the ahrimanic, materialistic way of thinking and want to keep it, would then be in league with everything which has come about through similar victories won over the dragon by Michael. They therefore would not unite with spiritual progress in human evolution but with material progress. And a time would come in the sixth post-Atlantean age when the only thing to please them would be to live in something which will have been brought about by bacilli, those microscopically small enemies of humanity.” 
“Exactly because of its logical consistency, and indeed its greatness, the scientific way of thinking, too, is in great danger of sliding into the ahrimanic way of thinking ... A time will come when we must have transformed our materialistic ideas to such an extent that we can progress to a more spiritual form of existence, but by then the earth will have been a corpse for a long time. It will no longer support us, and incarnations in the flesh such as we seek today will no longer be sought. But the individuals who have become so tied up with the materialistic way of thinking that they cannot let go of it will still sneak down to that earth and find ways of involving themselves in the activities of bacilli — the tubercle bacillus and others — bacillary entities which will be rummaging through every part of the earth's corpse. Today's bacilli are merely the prophets, let us say, of what will happen to the whole earth in future. Then a time will come when those who cling to the materialistic way of thinking will unite with the moon powers and surround the earth, which will be a burnt-out corpse, together with the moon. For all they want is to hold on to the life of the earth and remain united with it; they do not want to take the right course, which is to progress from the earth's corpse to what will be the future soul and spirit of the earth.”
“Things go in cycles or periods. Anything which happens in the physical world is really a kind of projection, or shadow, of what happens in the spiritual world ... Let us assume an event — for example the battle between Michael and the dragon — happens first of all in the spiritual world. It finally comes to an end when the dragon is cast down from heaven to earth. On earth, then, the cycle is brought to completion after a time interval which approximately equals the time between the beginning of the battle in the spiritual world and the time when the dragon was cast down. We might say: The dawn, the very beginning of this battle between Michael and the dragon, was in 1841. Things were particularly lively in 1845. It is thirty-four years from 1845 to 1879, and if we move on thirty-four years after 1879 we come to the mirroring event: You get 1913, the year preceding 1914 [the beginning of World War I]. You see, the developments which started in the physical world in 1913 are the mirror-image of the prime reasons for the spiritual battle.”
“Associated with each human being is an Angel who accompanies the same individual soul through all successive incarnations, and leads it to circumstances of destiny that give it opportunities to compensate imbalances from previous incarnations.
“...[A]n Archangel is associated with each cohesive group of human beings. This may be a large group, such as a country or a city; it may be a church congregation or a business corporation, even a very small group such as a family. Not all Archangels are of the same rank. The Archangel of a family is of course of a lower rank than the Archangel of a city.
“...[E]ach leading Archangel in turn guides human evolution for 354 years and four months. [This] sets the autumn of the year 1879 A.D. as the beginning of a Michael age. It is remarkable that this was known already in the early sixteenth century. Rudolf Steiner confirms that this indeed happened in late November of that year ... [I]n 1879 St. Michael became the supreme being whose rank towers above all other Archangels. This rank is often referred to as ‘time spirit.’” — Ernst Katz, “The Mission of Rudolf Steiner”, an essay based on a lecture given to the American Anthroposophical Society in 2004.
"As formerly man could speak of Jahve-Michael, the Leader of the age, so now we can speak the Christ-Michael. Michael has been exalted to a higher stage — from Folk Spirit to Time Spirit, inasmuch as from being the Messenger of Jahve he has become the Messenger of Christ. And so when we speak of a right understanding of the Michael Impulse in our age, we are speaking of a right understanding of the Christ Impulse.
"An abstract understanding always deals in names, simply in names, and thinks it will arrive somewhere if it asks: 'What kind of Being is Michael?' and wants to be told that he comes from this or that Hierarchy, that he is an Archangel, that Archangels have such and such qualities. Then it is all defined and people think now they know what such a Being is. They do not know it by speaking of Michael in this way. If one wants to understand the evolution of mankind, one must understand that Michael too has evolved: one must understand that it is the same Being who paved the way for the preparation of the Mystery of Golgotha, and who now in our day paves the way for the understanding of the Mystery of Golgotha. Then, however, he was a Folk Spirit, now he is a Time Spirit; then he was the Messenger of Jahve, now he is the Messenger of Christ. We speak of the Christ in the right way when we speak of Michael and his mission, knowing that Michael, who was formerly the bearer of the Jehovah-mission, is now the bearer of the Mission of the Christ.” — Rudolf Steiner, THE FESTIVALS AND THEIR MEANING, Vol. 4 (Anthroposophical Publishing Company, 1957), lecture 5, part 2, GA 152.
From a blog. This piece gives a pretty good description of the sorts of odd activities you may find in a Waldorf school.
The writer doesn't peer very far below the surface, and her idea of a gentle activity in Kindergarten (making swords) may seem a bit off.
Still, the piece has points of interest.
What Color is Your Dragon?
Once upon a time, a dragon menaced the countryside. The villagers cowered within their homes as the creature devoured the livestock and trampled the fields. Soon, the country lay in ruins; the king sued the dragon for peace, only to learn that the dragon required the sacrifice of the princess. A young man named George was chosen to champion the people. For his prayers and piety, he was granted a golden cloak and a sword of light by St. Michael and was given the courage to slay the dragon.
Michaelmas, the feast of the archangel Michael, falls on September 29. Fallen into obscurity since the 18th century, Michaelmas is still used to delineate the fall term in British universities – and it is celebrated with full force in the Waldorf schools. This slightly nutty preoccupation with rather obscure traditions is a hallmark of Waldorf education, but like most of the Waldorf traditions, has a purpose in marking the rhythm of the year, and the development of the child.
Michaelmas takes place at the beginning of the school year, as the children are gathering themselves to face the dragons of new challenges: new curriculum, new friends, and new projects. It also falls in autumn, and it is no coincidence that a sword of light is wielded against the destroyer of crops and livestock. Winter is coming, the days grow short, and soon we will be swallowed by the dark and the cold.
Though all of the grades celebrate Michaelmas, learning songs and watching the pageant, it is no coincidence that the grades in which the celebration of light and courage fall to those ages experiencing greatest change. The second graders are the villagers, the princess, and St. George. As they face the dragons of a scary world in which they are no longer certain that they believe in fairy tales or the magic of omnipotent adults (known in Waldorf philosophy as the nine-year change), they are given the courage to defeat the dragon before the entire school. The sixth grade are a fearsome monster. The hunger and unpredictability of the reptilian world of adolescence surges onto their horizon, and it is fitting that they should work together in lockstep beneath one skin as they are defeated or tamed by innocence.
The kindergarten has its own, gentler, and in some ways more meaningful, Michaelmas. Kindergarteners make swords. In the two-year kindergarten program, the older children, those who will brave the world of the grades next year, forge their own ‘swords of light’. During the week in which they hear and enact the story of St. George and the Dragon and learn songs and verses extolling the virtues of right and bravery, all of the children dye their own golden cloaks and the second-years rasp, sand, polish, and paint their wooden swords. These swords are stamped “by the blacksmith” with the symbol of each child, and are not seen as toys. The children will wield their weapons against the dragons of imagination, but they leave school on Michaelmas-day announcing that their swords are to be used “only for the right./ Not for some silly quarrel or fight.”
Standing by the straw-mulched vegetable garden in Sierra’s kindergarten yard, holding my big girl’s hand, I was taken aback to realize that she, and several of her second-year friends, were struck with attacks of clinging insecurity just as they were to receive their golden capes. As the teacher drew closer to our place on the ring, Sierra wrapped her arms tighter about my leg, her lip trembled, and she whispered, “I want Daddy.” I couldn’t figure out what was wrong; Mike isn’t gone, away, or lost. He was simply at work. Sierra loves her teacher, and she had been babbling all week about her cape and sword. Then, as I pondered my own dragons, it clicked. Accepting the symbols of courage, binding oneself to the task of slaying the dragon is often harder than the act of facing the beast, itself. And, I understood why the older children would receive their swords later, once the parents had left. It is almost impossible to draw upon one’s own courage when given a hand, or a leg, to hold.
A somewhat prettified Waldorf take:
From the publisher: "1879 marked the return of the solar spirit Michael — the archangel of the Sun — to oversee earthly evolution.
Steiner always placed his life and work in the service of Michael's evolutionary task.
And he recognized that, at the beginning of the twentieth century, humanity emerged from the Kali Yuga — the Dark Age — and entered the Age of Light."
Here is an item from the Waldorf Watch "news" page:
More on the Waldorf celebration of Michaelmas, this time discussed by the Washington Waldorf School (Maryland, USA):
"Michaelmas is not an invention of Rudolf Steiner. It is already there in the old church calendar, marking the fall equinox on September 29. It celebrates a battle between the hosts of angels in which the archangel Michael leas [sic] the good forces against the dark forces and casts the dragon out of heaven and onto the earth. The children, in fact, rarely hear this particular story, which occurs briefly in the Revelation of St. John. But what they do hear is a reiteration of its underlying theme in stories, drama, poetry, music, painting, and drawing.
"Michaelmas is the time of the year when we experience death in nature and approach of great outer darkness as the sun withdraws [sic] in both time and strength. It is a time of the year to be inspired to mobilize our own inner resources against those forces which seek to overwhelm us in the course of the working year. In summer we usually feel a little lazy and enjoy taking it easy. In autumn we often feel inspired to new heights of energy. By spring we are tired and need a boost from outside, and spring grants it. But in autumn we look straight into the coming darkness." [9-28-2011 http://www.washingtonwaldorf.org/Michaelmas.pdf]
The Washington Waldorf School is more upfront about its mystical views than are many other Waldorf or Steiner schools. Still, the Washington account of Michaelmas omits a lot. Michaelmas at Waldorf schools honors the Archangel of the Sun, Michael, who is the champion of the Sun God, aka Christ. According to Waldorf belief, Michael helps the Sun God ward off the evil effects of two mighty demons, Lucifer and Ahriman. Lucifer threatens humanity with false spirituality, Ahriman threatens humanity with the use of intellect (i.e., the rational brain). "Michael stands in this activity between the Luciferic World-picture and the Ahrimanic World-intellect." — Rudolf Steiner. [See "Michael". Also see "Sun God", "Lucifer", and "Ahriman".] One problem Waldorf schools must grapple with is that — awkwardly for "educational" institutions — they distrust the use of the brain. [See, e.g., "Steiner's Specific — Thinking Without Our Brains" and "Materialism U."]
For other reports on Michaelmas at Waldorf schools, see several earlier stories at the Waldorf Watch Annex. For an exploration of festivals in general at Waldorf schools, see "Magical Arts". For an indication of the ways Waldorf schools impress their doctrines on students through "underlying themes in stories, drama, poetry, music, painting, and drawing," see "Sneaking It In".
It is not irrelevant to note that Michael is particularly associated with Germany. Thus, one of the major German offensives in the First World War was "code-named 'St. Michael' after the sword-bearing archangel that was patron saint of the German Reich." 
Steiner was an ardent German nationalist who longed for German victory in that war. [See, e.g., "Steiner and the Warlord".] His admiration for St. Michael takes on a somewhat different hue when we consider the matter from this angle.
Germans embraced Michael as a new embodiment of the highest god of their pre-Christian faith. "In Germany, after its evangelization, St. Michael replaced for the Christians the pagan god Wotan, to whom many mountains were sacred, hence the numerous mountain chapels of St. Michael all over Germany."  [For more on the significance of ancient German beliefs, Norse myths, in Waldorf education, see "The Gods".]
 More typically, Steiner associated freedom with the effects of Lucifer. “Freedom is the result of the Luciferian influence.” — Rudolf Steiner, AN OUTLINE OF OCCULT SCIENCE (Kessinger Publishing, 1998: 1922 edition), p. 229. Ahriman and Lucifer are separate beings, but they represent sides of what is usually called the Devil. They are tempters whose activities may ultimately work out for our benefit (God or the gods can brings good out of evil), but they are nonetheless evil beings. This is why Michael must fight Ahriman.
 G. J. Meyer, A WORLD UNDONE (Delacorte Press, 2006), p. 522.
 "St. Michael the Archangel", THE CATHOLIC ENCYCLOPEDIA (http://www.newadvent.org/cathen/10275b.htm).
— Compilation and commentary by Roger Rawlings