The Assyrians too? Wow, how? I wonder if they traded up north through to the Black Sea
They were very much a land-based power, and marched armies off to distant locations, whipped the tar out of them, and then billed back the costs of the conquest by exacting tribute. The less a victim struggled, often the smaller the tribute would be. Those with high tributes often couldn't (or wouldn't) pay, and another Assyrian force would arrive to destroy the place and carry off everyone they didn't kill. It was a monstrously effective system, and very likely the world's first real multinational empire.