Did a medieval flying monk spot Halley's comet, twice? It's complicated

Early in the 11th century, a young Benedictine monk named Eilmer jumped from the 150-foot tower of his abbey in the small English town of Malmesbury, wearing a pair of crude wings he’d fashioned from willow wood and cloth. Eilmer managed to glide a good 600 feet, passing over the city wall before crash-landing in a small valley near the river Avon. The fall broke both his legs, crippling him.