1178, June 18: Five English Monks Witness an Explosion on the Moon
Gervase of Canterbury [1141-1210 CE] wrote of many things in his chronicles, some fantastic, some historical... and one thing is both.
Gervase tells us that in the year 1178 CE, five monks he knew came one day to tell him of something very unusual they had seen. It happened on June 18, when the monks were out at night; one of them glanced up at the crescent moon, and then called the attention of the others to it. In looking at the outer edge of the crescent moon, they saw another smaller crescent arise from it; this was followed by a flash of light and fire, followed by the whole visible part of the moon becoming wobbly and dark in appearance. None of the men were sure what to make of the event, but all wanted to be sure it was recorded.
Unlikely though it seems, most modern astronomers now believe that these five monks were in exactly the right place at exactly the right time to witness a large asteroid hitting the far side of the moon, a matter of fantastic luck for those now researching planetary collisions!