It's Richard Thompson's title, not mine. An interviewer asked him what his favorite song of the last 1000 years was, and he came up with his 1000 Years Of Popular Music concert. In the concert itself, he gives the date of this song as 1265 (I think... can't really remember)
Here's the full concert:
The man is a genius. He actually makes me like the Mills Brothers.
Then he does this completely unironic Britney Spears cover: