Also I did not just find, while going through my old poetry-in-translation files, the skeleton of a Highlander/Imperial Radch crossover that exists solely so that Methos can teach Breq these very old songs:
( some Valskaayan was feeling VERY BITTER about One Esk when they put this one into Radchaai the first time )
( Was Methos on Itra at the same time Breq was? There is that reference to pale-skinned outsystem merchants watching.... )
( This fits weirdly well with the events leading up to the declaration of the Republic of Two Systems, for a song that predates even the original Radch, although I guess that's the point. )