Iacchus is an epithet of Dionysus, particularly associated with the Mysteries at Eleusis, where he was considered to be the son of Zeus and Demeter. In a Paean to Dionysus discovered at Delphi, the god is described as being named Iacchos at Eleusis, where he "brings salvation".
"The route to Santiago was a Roman trade-route. It was nicknamed by travellers ‘la voje ladee, the Milky Way. It was the road under the stars. The pale arm of the Milky Way stretched out and pointed the way to the edge of the known world : to Cape Finisterre. We know that for pilgrims reaching Santiago in the Middle Ages it was as obligatory to venture on to the chapel of Nuestra Senora at Finisterre, the last finger of land crooked into the ocean. One explanation for this is that, there may have been an earlier journey to heaven, more mystical and of far earlier provenance than the church could have expected to acknowledge. The myth then must go back to earlier times and that the first pilgrims may have travelled the camino to Cap Finisterre even before the birth of Christ going as supplicants to some forgotten god."
"One such legend holds that walking the route was a pagan fertility ritual; this however is based on the explanation of scallop shell being a symbol of the pilgrimage. An alternative interpretation is that the scallop, which resembles the setting sun, was the focus of pre-Christian Celtic rituals of the area. The Pilgrims' road seems related to prehistoric cults of fertility arriving to Atlantic Europe from Mediterranean shores. Symbols of Ashtarte, the star within a circle, or Aphrodite,Venus coming on a shell,have been found along the roads to Compostela and among the ancient basques' mythology and legends,those related to Mari, the Mairu and the rising of Megaliths. Joseph Campbell associated the cult of Mari to that of Ishtar and Kali and in pre-Israelites times, the rejected consort of God called "the great prostitute", Asherah There is also claims that the pre-Christian origin of the Way of St. James was a Celtic death journey, westwards towards the setting sun, terminating at the End of the World (Finisterra) on the "Coast of Death" (Costa da Morte) and the "Sea of Darkness" (that is, the Abyss of Death, the Mare Tenebrosum, Latin for the Atlantic Ocean, itself named after the Dying Civilization of Atlantis)."
Wiki also has this:"In Fulcanelli's Mystery of the Cathedrals the pilgrimage to Compo-stella is decoded as a metaphor for one of the processes for making the Philosopher's Stone, namely the method using antimony. This method will produce stellated crystals in the arm of the retort, which are then further worked upon. A common misunderstanding which mislead many, including Newton, is that the "stellate regulus" of antimony is the matter to be used.
The pilgrim's shell was a motif used by the alchemist Jacques Coeur on the many buildings he erected, and was his personal motif; it is also the shell upon which Venus rides as she rises from the sea (morning star = stellated matter); this ocean is green, the color of many Venusian minerals, but it's meaning is deeper. Basil Valentine said that the alchemists called their first matter by the name of anything green to confuse the ignorant, but in truth there is such a first matter that is a green esculent water. Venus represents the generative force, the power of attraction/repulsion which brings forth the cosmos. Her water is that of the Fire of Desire which motivates this push and pull. The shape of the calabash carried by the pilgrims is another clue to the source of this green water.
It was also common for churches to place holy water in a container shaped like this shell, although it is unlikely most clerics would know why. This holy water (imbued with the Spirit) was another metaphor for the Mercury of the Philosophers."
'This goal is a strange substance, which the Chemistry of men ignores, which they have never analyzed, and which they will perhaps ignore forever. It is a substance which university theses do not describe, and whose very name makes the profane smile. This substance is the “Chrysoprase”, the Philosophers Stone.
To obtain these fine crystals, of the color of ruby, to which the shadows instantly reflect back their mysterious luminescence, the artisan of the Great Work will have met strange companions along the way: such as the Archons who stand watch over the successive thresholds of the intermediary worlds, the better to bar the way to the seeker, innumerable and symbolic personalities: the Crow and the Swan, the Lion and the Dragon, the King and the Queen, etc., each of which poses their particular enigma for him to solve!
It is only after having understood the secret meaning these that the pilgrim will finally see rise, shining in the heart of the metallic shadows, the Star of Compostella, which announces the end of the golden periplus.
Yet, divorced from any rational basis, and without any possibility for industrial application, the procedure employed nevertheless constitutes a real spiritual enrichment for the Hermeticist, since Life will eventually deliver one of its greatest secrets to him. Now transmuted by this second Revelation, the Initiate finally becomes the Adept, and, in the plane of his inner spiritual alone, with the Arcana finally conquered, he can finally become transformed, to become and remain forever: the Illuminated One.
As the mysterious Stone engenders and multiplies itself in continuous mathematical progression; the Illuminated One, in his turn, transmits his own spiritual light to those who, intelligent and docile prima materia, will themselves accept the need to die as lead in order to be better reborn as gold…
The pilgrimage of St. Iago of Compostella, is one of those enigmatic myths of the quest of the Great Work.
Pilgrims wear a scallop shell as an emblem, also called mérelle. And in the
middle of the matras, as the beginning of The Work, upon the finally decomposed prima materia, a crystalline silver star must appear and float upon the surface – a first indication that the Operator is on the right path…'
This is just a potted version, and the Green Language is worth a study on its own.
There are political reasons which are always to be found at the root of this kind of 'Christianising' event.
'It's not hard to see how closely the fates of Spain and the pilgrimage are entwined. Most of Iberia falls to the Moors, some resistance is offered by the Carolingians but their descendants become preoccupied with their own power struggles, Christianity is limited to coastal regions in N Spain, beset by marauding Vikings. Moors are part of the Arab and African world; Christians, part of Europe. Which way will Spain go? Into this situation steps the Church. Very conveniently, the tomb of one of the more important apostles is discovered right in the far NW corner of the peninsula. The pilgrimage is strongly encouraged by both church and state, promoted by monastic orders such as Cluny, and policed by orders of knights. The reconquest of Spain is billed as a crusade because it is the home of Santiago, almost as important as the Holy Land. And the pilgrimage is an integral part of efforts to link Spain with Christian Europe. Without the Moorish invasion, Santiago would probably not exist. And without the links beyond the Pyrenees, in which the pilgrimage played a leading role, Spain might very well now speak Arabic and Galicia might very well be part of Portugal.'
Oh and one last little snippet of interest...The relationship between the geographical area of the ancient Galician Finisterrae and the cult of Saint James was established shortly after the discovery of the apostle's tomb. Local traditions, possibly from the Swabian era (5th-6th century A.D.), indicate St. James the Apostle's connection to this area. In the 10th century A.D., new tales appeared regarding his presence and, halfway through the following century, the definitive version was set down in Book 3 of the Codex Calixtinus. Thus, Fisterra has become a solid part of the European Pilgrim's Way of St. James.The various stories of how St. James's body was carried to Galicia mention the pagan town of Dugium (Duio), which lay on the isthmus of Fisterra, and from which various remains have disappeared. According to the Codex Calixtinus, when the disciples of Zebedee came ashore at Padrón, Lupa, queen of that area, sent them to Duio so that the Roman legate would authorise them to bury the Apostle. The legate threw them into jail, intending to kill them, but they were freed by an angel and escaped. When the soldiers in pursuit of them were about to catch up with them, they crossed the bridge of Nicraria (which has been identified as the Roman bridge at Ons, now sunken beneath the waters of the Barié de la Maza reservoir). Providentially, the bridge collapsed just as the soldiers were crossing it.