The earliest printed account is William Harrison's, in the second series of Mona Miscellany published by the Manx Society in 1873, under the heading Caillagh-ny-Gueshag, a Manx Prophet. Harrison compared her to Mother Shipton, said she had been held in great veneration in her day, and admitted that who she was and where she lived had been forgotten. His material came from John Quirk of Carn-ny-Greie, who told him of a small chapel called Cabbal-cheeill-Vout near the Foxdale river in Kirk Patrick, between Ballahig and Slieau Whallin, of which the Caillagh was said to have predicted that when it was washed away by the stream the Quirks would no longer remain in Slieau Whallin. The last proprietor was often reminded of it, and used to say that as much of the chapel remained as he could cover with his big coat, until a flood swept it away and the last of the Quirks died without issue soon after, about sixty years before Harrison wrote. Two more sayings followed, that there would be a smithy chimney in every house before the end of the world, and that out of grey stones people would get their bread. She had also predicted that Manx people would travel dry shod from the Point of Ayre to Scotland, and the first series of 1869 had already given the proverb, in its own words, that "the Manx and the Scotch will come so near as to throw their beetles at one another".

A. W. Moore took the material over in 1891 under the spelling Caillagh-ny-Ghueshag, explaining that caillagh meant an old woman and had come to mean a hag or witch, and that hers was the name of the most famous of them, the old woman of the spells or the Sorceress. He placed her in the higher order of magical beings with Manannan and the enchantress Tehi Tegi, a sorceress or rather prophetess, a sort of Manx Mother Shipton who appeared to have been superior to most of her kind. She was an adept at chiromancy, faaishlaght, and could perform a charm or incantation, pisag, but her posthumous reputation rested on what she had foretold, which Moore thought related to very trifling events. He repeated the Keeill Vout prophecy, dating the disappearance of the chapel and of the Quirks of Slieau Whallin to about seventy years earlier, the smithy chimney, the bread from grey stones and the beetles, adding drily that the Point of Ayre was extending slowly towards Scotland but that thousands of years would be needed.

Sophia Morrison's Manx Fairy Tales of 1911 gave the figure a new name, a new sex and a new home. Her Caillagh-ny-Faashagh was the greatest wizard of all in the old days, who lived not above ground but in a quarry, in a hole under the rock on the lonely mountain side, which was why people called him the Prophet Wizard of the Wilderness. At dark he roamed the mountains crying Hoa, hoa, hoa like the bellow of a goat, in a voice so terrible that the earth trembled, and he could take any shape he liked, a goat with eyes as big as two dishes that followed a man's lantern along the mountain road, or a man as tall as two men who chased a woman at Garey Mooar. He would not foretell unless asked. He had foretold the battle of Santwat in 1098, when the Neb ran red from Glen Crew to the sea, and the finding of the Foxdale lead mines, telling a man who asked how he would get rich that the riches of the Isle of Mann lay hid behind Barrule, and, in Morrison's words, "a battle between the Irish and the Manx at Creg Malin". To an old maid who cast lead spoons he foretold the end of the world, when the mountains would be cut over with roads, iron horses would gallop over them, and there would be an inn on the top of Snaefell. Mann and Scotland would come so close that two women could wring a blanket between them, and the chief rulers of Mann would be compelled to flee.

W. Walter Gill, in 1929, brought the names back together. Fai'ag, he wrote, was a pronunciation of faihtag, prophecy, so that Morrison's Prophet of the Wilderness and the weather hag of the first of February, the Caillagh ny Groamagh, and Harrison's old woman of the spell were all much the same personage, so far as such shadowy abstractions could be classified. He added one more saying attributed to her, that three feet of Finn's feet from the wall of Rhullick y Dhoon, the earthwork on the crown of South Barrule, lay all the treasure of the Isle of Man, which he took to be a prediction of the Foxdale mines. What the sources show is a cluster of prophecies about the Foxdale and St John's country, attached in the 1870s to an unnamed old woman whose name was already only a name, and by 1911 to a goat-shaped wizard whose cry of Hoa, hoa is the cry Train had recorded in 1845 for the dooinney-oie, the night man of the mountains.