A related story tells that the dun-colored cow was owned by a giant. Its supply of milk never ran out, and anyone could come and milk it to get what they needed. One day, however, a witch came along. After filling her pail with milk, she wanted the cow to fill her sieve (called a "riddle"); its attempts to fill what could not hold milk killed it.
The origin of Guy's encounter with the Dun Cow is unknown. One 19th century philologist suggested that "Dun Cow" was a corruption of Dena Gau, Germanic for "Danish region"; in his explanation, the character of Guy was instrumental in defeating the Danes. Since one version of Guy's legend has him returning from a pilgrimage to the Holy Land to help King Æthelstan against northern attacks (Danes), this makes some sense.
But the legend gave rise to stories about actual beasts, and so we have to look at non-Danish options. There are actually "souvenirs" of the Dun Cow in England. At Warwick Castle, where you can see items reported to be from Guy's life and adventures, there is one item that is said to be the rib of the Dun Cow. It is, in fact, a narwhal tusk. In Lancashire there is a Dun Cow Rib Farm where a giant rib bone is embedded in a wall, said to come from a giant cow. That rib is assumed to have come from a giant bovine, the auroch that roamed Britain during the Bronze Age.
There is a modern novel called The Book of the Dun Cow, adapted from "The Nun's Priest's Tale" from Chaucer's Canterbury Tales. There was also a 12th century Book of the Dun Cow that is a lot more relevant to this blog, and I'll tell you about it next time.
