I know very little about folk music, and I'd like to ask your advice. Specifically... could anyone suggest a very short list of 10 "most important" English folk songs, representative of the major genres (ballad etc.) and different periods? I guess "Barbara Allen" might be in there, but there my knowledge stops!

[By English I mean originating from the country called England. My interest is basically in pre-20th-century songs. And of course I realize that 10 is a very small number.]

Many thanks for your time and opinions!

Ben