And whan this mayden sholde unto a man
Ywedded be, that was ful yong of age,
Which that ycleped was Valerian,
And day was comen of hir marriage,
She, ful devout and humble in hir corage,
Under hir robe of gold, that sat ful faire,
Hadde next hire flessh yclad hire in an haire.

– Geoffrey Chaucer

The Canterbury Tales, The Second Nun’s Tale. Cecilia is betrothed to a man named Valerian. On the day of her marriage under her robe of gold, she wears a coarse hair shirt next to her skin. These were shirts of rough cloth or animal hair which religious people used to wear to punish themselves and do penance.