Making contact across a gulf of time can be a deeply weird sensation. Abbess Hildegard of Bingen was a very religious lady who lived in, well, Bingen in the twelfth century, and specialized in mystic visions of the Celestial City. Like a tourist taking snapshots, she carefully sketched its glowing architecture – preserved for the ages as woodcuts in her books Scivias (circa 1180) and Liber divinorum operum, the Book of Divine Works.
I was introduced to Hildegard by Bob Shaw, the popular science fiction writer who died early in 1996. The first Shaw sf novel I read, long before meeting him, was his 1969 The Two-Timers, whose hero has what you might call visions of the Celestial City and – after lots of library research into past visionaries, including Hildegard and Blaise Pascal – develops his mystic insight into a method of time travel.
It turned out that Bob used this rather odd basis for traditional sf hand-waving about timeslips because, approximately twice a year, he used to see those visions of the Celestial City, and had researched them in the library. Cannibalizing interesting bits of autobiography is one of the things all writers do....
Here the page ripples and wavers to denote the passing of many years, during which I forgot all about Hildegard and The Two-Timers, until one day the Celestial City sneaked up behind me with a well-weighted cosh. It was one of those sessions when I'd been overdoing freelance writing a trifle – eight hours solid at the word processor, as emphatically not recommended by doctors – and paused for some chore like addressing an envelope. This proved difficult, because all of a sudden there was something shimmering and multicoloured between my eyes and the paper ... a kaleidoscopic light-show, rippling and growing to obscure the remnants of my ploughed-up field of vision.
It seemed an excellent time to panic. Had Alien Greys implanted radioactive devices in my eyes? Were orbital mind control lasers insidiously taking over my visual cortex? Or was it just a dose of perfectly ordinary hallucination, DTs or detached retina? None of these options seemed altogether encouraging.
What eventually stopped me gibbering with fear was the memory of Bob Shaw and Hildegard of Bingen ... and the realization that without recognizing it, I was seeing Hildegard's Celestial City. The flickering stained-glass blur had a jagged border, full of re-entrant angles, rather like a ground plan of old-style military fortifications. Someone in the eighteenth century had indeed named these images 'fortification figures': Dr John Fothergill, who attributed them to eating too much buttered toast for breakfast. Other names, usefully listed in Bob's novel, included teichopsia and scintillating scotoma ... that is, a (temporary) blind spot that seems lit-up rather than dark.
In fact, what Bob and Hildegard had had all their lives and I'd just met for the first time was hemicrania sine dolore, the posh way of saying a half-head headache without the actual headache – or, to put it less obscurely, classical migraine lacking the usual pain and nausea. Instead, there's often a feeling of intense oddness ... like jamais vu, the sense of never having been here before, even when 'here' is a familiar place.
Hildegard religiously assembled her pictures of the fortified Celestial City from fragments of these glittering visions. She drew other apocalyptic images based on what modern medics can identify as known variations on the hemicrania sine dolore light-show: for example, a sinister shower of black stars or negative scotomas. Some of the most telling of the resulting woodcuts are reproduced in Oliver Sacks's Migraine and The Man Who Mistook His Wife for a Hat.
It is, of course, incumbent on Forteans to be distrustful of brisk scientific explaining-away – though 'migraine' isn't a full explanation, since the root causes remain obscure. (A Doctor Writes: 'Er, it's vascular, innit?') The curious thing about Hildegard's visions is that instead of the usual nausea and pain, or the peculiar disorientation I get myself, she enjoyed waves of rapturous, religious ecstasy. Devout Christians would presumably think it entirely reasonable that God should use the mechanisms of migraine to enlighten Hildegard. Others might see the lesson as being that plenty of internal effects can mess with one's head, before considering weird new external phenomena.
Myself, I confess to severe panic when my own 'rational' view of the world was jolted by the arrival of those marching coloured lights. Good old Bob Shaw and Abbess Hildegard provided a soothing explanation, and I'm eternally grateful. Now the visual disturbances are practically old friends, even if my encyclopedia does insultingly claim that: 'migraine aura without headache occurs mostly in elderly persons.' Elderly? Elderly? What do these ignorant doctors know?