Adventures of Isabel

Guess where, and when, the following lines were written (in literal if not literary translation):
This unredeemed people
may perhaps succumb in the struggle,
but only its corpse
can be yoked by alien tyranny.
Yankee! If you defeat us
with the powerful weight of weapons,
you will not live happily, because you are hated
even by the air of my native land.
Yankee! [...]