So what is this 'Great Work' the Pamphleteers are yammering on about in the dawning years of the 1600s?
Well, it's a term borrowed from medieval alchemy where it usually defined as such.
Great Work: The Great Work (Latin: Magnum opus) is an alchemical term for the process of working with the prima materia to create the philosopher's stone. It has been used to describe personal and spiritual transmutation in the Hermetic tradition, attached to laboratory processes and chemical color changes, used as a model for the individuation process, and as a device in art and literature. The magnum opus has been carried forward in New Age and neo-Hermetic movements which sometimes attached new symbolism and significance to the processes.
This is where things get a might tricky. You see, Occultists rarely use words like everyday, common-sense lay-people use them. They hide the meaning in double-speak and metaphor. They burry the dog. And different sects of Occultists will use the same language to mean different things.
The thing to understand about medieval 'Alchemy' is that isn't at root a sort of mystical chemistry. Practitioners of such 'natural magic' certainly existed, but what this 'Great Work' refers to, the act of transmuting base 'lead' to 'gold' with a 'philosopher's stone' actually refers to the secrets of double entry book-keeping and compounding interest. The magic here is show liabilities as assets, accounts payable as accounts receivable. This then is the 'transmutation' of 'lead' (something valueless) to 'gold' (something precious).
But this is not what the Rosicrucians mean by 'Great Work'. No the Rosicrucians are referring to the transmutation of a very different type of matter; namely, the mystical body of Christ, the bride of Our Lord, the Church. The Rosicrucians seek to 'transmute' the body of 'exoteric', 'ritualistic', 'medieval', 'superstition', 'dogma' into an 'enlightened', 'free', 'scientific', and 'rational' body, a 'Christian Science' if you will.
But don't take my word for it. Let's look at another Pamphlet, this time titled 'Chymical Wedding of Christian Rosenkreutz' or der Wedding for short. First published in 1616, der Wedding presents itself as an allegorical romance divided into works of Seven Days (cough Genesis, cough), and recounts how our narrator, one Christian Rosenkreuz, is invited to attend the “Chymical Wedding” of the King and the Queen, at a mystical, magickal, miraculous castle.
Side Note - the King and Queen mentioned here aren't just stock Romance characters, but intended to represent the aforementioned Frederick V of Bohemia and his spouse, Elizabeth Stuart of England. But we'll let that thread lay fallow for now. Don't worry, we'll be back. Just keep it in mind, these pamphleteers aren't just pie in the sky ivory tower academics building castles in the sky, they're advocating real politics with real and bloody battlefield results.
Side Note the Second - In the story presented by the pamphlet, the invitation received by Christain Rosenkreutz is sealed by the alchemical glyph called “Monas Hieroglyphica” devised by one Dr. John Dee. Again, put a pin in that, we'll be back.
Side Note the Third - The events of der Wedding, although published in 1616, take place over 150 years earlier, in 1459. What else happened that year? The Constitutions of the Freemasons of Strasburg was first signed in Regensburg, with a second signed shortly afterwards in Strasburg. Yep, we'll be back.
The account follows the traditions of Passover and the seven days of unleavened bread exactly as per instructions for the Passover ritual in the book of Exodus (Exod 12:15). The slaughtering and roasting of the Paschal lamb begins in the evening (near Easter), as does The Chymical Wedding itself. The Chymical Wedding begins in the evening with CRC sitting at a table with both the Paschal Lamb and the unleavened bread.
But what is the meaning of this allegorical ritual? Again, let's let the text speak for itself.
By us the Bridegroom offers you a choice between four ways, all of which, if you do not sink down in the way, can bring you to his royal court. The first is short but dangerous, and one which will lead you into rocky (note: PETER - ROCK) places, through which it will scarcely be possible to pass. The second is longer, and takes you circuitously; it is plain and easy, if by the help of the Magnet you turn neither to left nor right (note: the Gospel of John does not mention the thieves to right and left of Jesus). The third is that truly royal way (note: Epistles of Peter, James, Jude, and John and their use of similar language) which through various pleasures and pageants of our King, affords you a joyful journey; but this so far has scarcely been allotted to one in a thousand. By the fourth (Epistles of Paul) no man shall reach the place, because it is a consuming way (Heb 12:29), practicable only for incorruptible bodies (I Cor 15:52). Choose now which one you will of the three, and persevere constantly therein, for know whichever you will enter, that is the one destined for you by immutable Fate, nor can you go back in it save at great peril to life.
What this passage is proposing is a rejection of the authority of both Scripture and Tradition, replacing them with the propositions of 'right reason' as judged by each and every man, acting as his own authority, sifting the deposit of the faith without regard to her teaching authority, her magisterium. This then is the modern self-willed rationalism that has been condemned by the Church over and over again.
We may contrast this with the following.
1Now the serpent was more subtle than any of the beasts of the earth which the Lord God made. And he said to the woman: Why hath God commanded you, that you should not eat of every tree of paradise? 2And the woman answered him, saying: Of the fruit of the trees that are in paradise we do eat: 3But of the fruit of the tree which is in the midst of paradise, God hath commanded us that we should not eat; and that we should not touch it, lest perhaps we die. 4And the serpent said to the woman: No, you shall not die the death. 5For God doth know that in what day soever you shall eat thereof, your eyes shall be opened: and you shall be as Gods, knowing good and evil.
6I wonder that you are so soon removed from him that called you into the grace of Christ, unto another gospel. 7Which is not another, only there are some that trouble you, and would pervert the gospel of Christ. 8But though we, or an angel from heaven, preach a gospel to you besides that which we have preached to you, let him be anathema. 9As we said before, so now I say again: If any one preach to you a gospel, besides that which you have received, let him be anathema.
THE EPISTLE OF SAINT PAVL TO THE GALATIANS 1:8-9
8. But although we, or an Angel from Heauen, euangelize to you beside that which we haue euangelized to you, be he anathema.
9. As we haue said before, so now I say againe: If any euangelize to you, beside that which you haue receiued, be he anathema. ~ ORIGINAL DOUAY RHEIMS BIBLE (1582 & 1610)