Most musical-instrument historians, of which there are several, will tell you that the earliest surviving examples of what would today be considered a trombone (or, more properly in their day, a sackbutt) were made in the 1550s. A handful of writings refer to Belgian musicians of a century earlier playing a “saxbutt”, though they are often dismissed as unsubstantiated revisionist scribbling. In truth, these writings are part of a sophisticated web of ethnomusicological sleight-of-hand spun to hide the existence of a cult so hideous that it would freeze the very lymph in your nodes.

Cast your imagination back, then, to the year 1534. Already seeking to establish firmer control over the Church, Henry VIII had entrusted his chief minister, the Earl of Essex Thomas Cromwell, with the task of assessing the wealth of monasteries around England and Wales. In the course of Cromwell’s travels and research, he unearthed (and, some have argued, fabricated) countless tales of ecclesiastical avarice and impropriety that conventional wisdom suggests were used to justify Henry’s imposition of taxes and the eventual dissolution of the vast majority of the monasteries. What he actually found was something altogether more sinister.

Abbot Huhnkopf, c.1393

The Benedictine monastery of Chepstow — the first Norman house in Wales — dated back to the time shortly after the Norman conquest. Established around 1070 CE on the land of Earl William fitz Osbern, it became an independent priory some 370 years later. In the mid-1390s, however, a Benedictine monk by the name of John Workman was given keepership of the farm connected with the priory, and it was through him that Chepstow’s disquieting history began. Recent scholarship suggests that Workman was, in fact, the assumed name of Johann Huhnkopf, the first in a long line of heretical ne’er-do-wells who dabbled in both musical theory and gnosticism.

Abbot Huhnkopf’s writings suggest a belief in higher spiritual states that could be attained through musical means. Where most recent research in the field has concentrated on the psychoactive properties of drones and lower frequencies, Huhnkopf was convinced that higher-pitched sounds could break down “a Manne’s consciouse Minde and sette it to Dreaminge” (Regis, 1991). Not content to simply theorize, Huhnkopf and his monastic coterie are known to have experimented with a variety of flutes and horns in a series of attempts to induce such a state, though it was not until the mid-15th century that their efforts bore fruit.

Abbot Froschgalle, c.1441

In late 1440, then-Abbot Froschgalle (publicly known as Shrewsbury) wrote in his journal that “a fluted Bone has piercet the Veille” (Pilkey, 2006). After several decades of tinkering with assorted materials and configurations, including an extended dalliance with thighbone trumpets (“kangling”) which bear a curious resemblance to those found in latter-day Tibetan Buddhist funerary customs, it seems that Froschgalle and his minions had chanced first upon the mind-altering tone produced by a thick bone flute, and had then subtly altered both its pitch and the resulting effects with a hollowed-out screw cap that minutely adjusted the flute’s length. Trances and “Dreames most vivide” (Hess, 2010) were said to result from ceremonies involving this bone flute, and subsequent writings even hint at Froschgalle having sensed or seen other planes of existence.

It was under the influence of these bone visions that Chepstow declared itself a fully independent monastery in 1442. Working in the relative privacy of southeastern Wales, Froschgalle and his order set about trying to project their “dreamming selves” into what they saw as “Lands beyonde” (Hess) by way of sleep deprivation, near-starvation, and long exposure to the sounds of their “traum-bone”. (Incidentally, it was around this time that monk and poet John Lydgate is known to have visited Chepstow, and his use of the word “talent” to describe a gift of natural ability has been taken by some to imply a horrified reaction to Froschgalle’s altered states of consciousness.) Replacing the earlier tuning cap with a second, hollow outer layer of bone that could be extended to a variety of lengths, it was reasoned, would allow the players greater control over an extended range of induced states, and a frenzied period of experimentation and fine-tuning ensued.

Records of the latter half of the 15th century in the monastery are scattered, but it is clear from several writings that, at some point before 1500, the monks’ psychic expeditions saw them make contact with a dark and hungry force from another place. The earliest surviving reference to Gonpo is from 1501; a member of the order whose name remains unknown writes of “the Sighte of three Eyes in a blue Cage”, and other contemporary fragments mention “Fanges in the Darke” and “hair lit alike the Skye” (Pilkey), all of which hints at what Tibetan Buddhists would call Gurgyi Mgon Po, and which the Chepstow monks began calling “Gonpo” in their writings and rituals by 1503.

Gurgyi Mgon Po

Tibetan writings typically describe Guygyi Mgon Po as bearing several monstrous ornaments, among them a garland of severed heads, a cup and a crown both made of skulls, and bone objects that are very plainly flutes similar to those used by the monks. With the flutes, a continental monk named Ziegenbauch claimed in the early days of 1505, “we shall crosse to the demesne of Gonpo and in turn He shall crosse and laye Claim to this” (Hess). In a few short years, the Gonpo cult appears to have spread well beyond Chepstow and across much of England, but the principal groundwork for their terrible notion of what would come next was still being laid in Wales.

“His Kingdome shall be of Fyre and Bloode, enterring the Dreames of Menne”, wrote an Abbot Duncan in 1521, and it was around this time that widespread production of a metal version of the dream-shaping bone flute went into effect, presumably in lieu of the thighbones of respected teachers and/or criminals who had died violently, which one suspects would have been hard to acquire in quantity. Casting the instruments — ha! — of man’s impending doom in common brass no doubt appealed to some monk’s twisted sense of humour, referencing the trumpets that would be sounded as hail and fire laid waste to the world and the sun and moon were darkened in the Book of Revelation. Gonpo’s fiery entrance into the minds of men would accompany the world’s Biblical descent into eternal night, or so the evolving legend went.

Thankfully, as horrific cults are wont to do as they grow and splinter geographically, the focus of the Gonpo monks seems to have drifted towards more earthly matters. The windows above the elaborate arched doorways to the priory church, depicting bizarre lights in the sky and monks wreathed in an otherworldly fire, are a testament to the ever-increasing wealth of the monks, and the bodies of deceased monks, previously interred in the barrows north of the church, were being exhumed and elaborately anointed with oils for the coming of the fiery times. Local songs and folklore tell of late-night ceremonies in the woods involving the wearing and drinking of blood (“sip and bathe in the Hart’s Wine”), the burning of animals atop a summertime pyre made of yew branches (“the Connes and Berrys lickt by the Fire with Oxen”), and (likely apocryphal) cannibalism and bestiality. It was into this scene that Cromwell stepped when he was sent to survey Chepstow and its holdings in May of 1536.

Doubtless shaken by the inhuman things he had witnessed there, Cromwell petitioned for the monastery’s dissolution immediately upon his return to Henry’s court, a request which was granted in September of that year. “I am convinnced that Chepstow must be sette ablaize”, he wrote in a letter to the king in June, and while the building itself was never put to the torch, a large detachment of armed men was sent to clear the grounds when the monastery was suppressed, and local etchings show pyres burning late into the night for several days, perhaps as the contents of the tunnels beneath the church were cleared of blasphemous artifacts.

At least six monks are known to have been put to death, and an equal number dispersed to serve in small parishes in the surrounding area, but church documents do not speak of what became of Wilhelm Käsehut, the abbot of the day and a noted oenophobe. Vague passages in several forbidden texts suggest that he fled to Tibet, there to resume his efforts to bring about the downfall of man by way of extra-dimensional musical travel, and little is known about what became of the order at that point, but at least in Europe, the group appears to have been almost entirely put down. Their abominable instrument, however, had already found its way into popular consciousness, and we live now in a world that is at any moment a few experimental slide positions away from extra-dimensional madness and horror.