Eric (Discworld, #9; Rincewind, #4)

by Terry Pratchett

No enemies had ever taken Ankh-Morpork. Well, technically they had, quite often; the city welcomed free-spending barbarian invaders, but somehow the puzzled raiders always found, after a few days, that they didn’t own their own horses anymore, and within a couple of months they were just another minority group with its own graffiti and food shops.