Didascalicon, Book III: the art of study (discipline and method)
Chapter XX. On exile
Last of all, a foreign land is set down, which also exercises a man. The whole world is an exile for those who philosophize. Yet, as one says:
I know not by what sweetness the native soil draws all, and does not suffer them to forget it.
It is a great beginning of virtue that the exercised mind learn little by little first to change these visible and transitory things, that afterwards it may even leave them behind. He is still delicate to whom his native land is sweet. He is strong to whom every soil is his country; but perfect, to whom the whole world is an exile. The first has fixed his love on the world, the second has scattered it, the third has extinguished it. I have been an exile from boyhood, and I know with what sorrow the mind sometimes leaves the narrow ground of a poor hut, with what freedom afterwards it despises marble halls and paneled roofs.