Taak any bryd, and put it in a cage,
and do al thyn entente and thy corage
to fostre it tendrely with mete and drynke
of alle deyntees that thou kanst bithynke,
and keep it al so clenly as thou may,
although his cage of gold be never so gay,
yet hath this brid, by twenty thousand foold,
goon ete wormes and swich wrecchednesse.
for evere this brid wol doon his bisynesse
to escape out of his cage, yif he may.
his libertee this brid desireth ay.
- Chaucer, Manciple's Tale of the Crow.