Loreena McKennitt: The Bonny Swans
Here's our missing sin: Envy.
The Bonny Swans is a murder ballad about sexual jealousy. Childs lists it as #10 of his 305 Popular English and Scottish Ballads, and the original version goes way back to 1656 or thereabouts (Childs labels it "The Twa Sisters"). Here's Wikipedia's summary of the gruesome plot:
Two sisters go down by a body of water, sometimes a river and sometimes the sea. The older one pushes the younger in and refuses to pull her out again; generally the lyrics explicitly state her intent to drown her younger sister (over a suitor)…When the murdered girl's body floats ashore, someone makes a musical instrument out of it, generally a harp or a fiddle, with a frame of bone and the girl's "long yellow hair" for strings. The instrument then plays itself and sings about the murder…so that the elder sister is publicly revealed.
This song clearly violates two of the many warnings from this wonderfully amusing list, Things I've Learned From British Folk Ballads", to wit:
Avoid navigable waterways. Don’t let yourself be talked into going down by the wild rippling water, the wan water, the salt sea shore, the strand, the lowlands low, the Burning Thames, and any area where the grass grows green on the banks of some pool. Cliffs overlooking navigable waterways aren’t safe either.
Sharing a boyfriend with your sister is a bad plan.