Medieval Monk Who Built Wings and Glided 600 Feet May or May Not Have Seen Halley's Comet Twice

In the early 11th century, a young Benedictine monk named Eilmer decided that the 150-foot tower of Malmesbury Abbey was the perfect launchpad for his homemade wings - crafted from willow wood and cloth. He glided a respectable 600 feet, cleared the city wall, and crash-landed in a valley near the river Avon, breaking both legs. The abbey still commemorates him with a stained-glass window, presumably with a caption reading "Well, that didn't go as planned."

Our source for this tale is 12th-century historian William of Malmesbury, writing around 1125. William was kind enough to mention that Eilmer, "advanced in years," saw Halley's comet in 1066 and remarked, "It is long since I saw you." Some historians took this to mean Eilmer also spotted the comet during its 989 fly-by, when he would have been a young boy. Assuming he was at least five in 989, he'd have been born no later than 984, making him in his 80s by 1066, with his flight occurring between 1000 and 1010.

But James Aitcheson of the University of Leicester, writing in Notes and Queries, suggests Eilmer might have seen a different comet - the comet of 1018. That one was visible in the British Isles for about two weeks in the fall, and Eilmer may have simply assumed it was the same comet he saw in 1066 (which left him "crouching in terror at the gleaming star"). If so, Eilmer could have been born in the early 1010s, making him over 50 in 1066 - still consistent with being "advanced in years."

This would dash recent speculation that Eilmer understood Halley's comet's periodicity centuries before Edmund Halley. Aitcheson notes that while Eilmer could have accessed historical comet records, William of Malmesbury doesn't mention any astronomical hobby. "Indeed, it is not clear that sky-watchers in the Early Middle Ages were able to tell one comet apart from another," Aitcheson writes. A later birth date also makes it just possible that Eilmer lived to age 90, met William in person, and "directly passed on the story of his pioneering feats of aviation." So, Eilmer's Comet? Probably not.