“Ankh-Morpork, alone of all the cities of the plains, had opened its gates to dwarfs and trolls (alloys are stronger, as Vetinari had said). It had worked. They made things. Often they made trouble, but mostly they made wealth. As a result, although Ankh-Morpork still had many enemies, those enemies had to finance their armies with borrowed money. Most of it was borrowed from Ankh-Morpork, at punitive interest. There hadn’t been any really big wars for years. Ankh-Morpork had made them unprofitable. Thousands of years ago the old empire had enforced the Pax Morporkia, which had said to the world: ‘Do not fight, or we will kill you.’ The Pax had arisen again, but this time it said: ‘If you fight, we’ll call in your mortagages. And incidentally, that’s MY pike you’re pointing at me. I paid for that shield you’re holding. And take my helmet off when you speak to me, you horrible little debtor.’”

— Terry Pratchett, Feet of Clay