The 374 AD and 607 approaches each came within 0.09 AU of Earth. The 451 AD apparition was said to herald the defeat of Attila the Hun at the Battle of Chalons. The 684 AD apparition was recorded in Europe in one of the sources used by the compiler of the 1493 Nuremberg Chronicles, which contains an image 8 centuries after the event. Chinese records also report it as the "broom star". In 837, Halley's Comet may have passed as close as 0.03 AU (3.2 million miles; 5.1 million kilometres) from Earth, by far its closest approach. Its tail may have stretched 60 degrees across the sky. It was recorded by astronomers in China, Japan, Germany, the Byzantine Empire, and the Middle East; Emperor Louis the Pious observed this appearance and devoted himself to prayer and penance, fearing that "by this token a change in the realm and the death of a prince are made known." In 912, Halley is recorded in the "Annals of Ulster", which state "A dark and rainy year. A comet appeared."