If we add that an expedition into a foreign country offers the additional advantages of escape from your exacting creditors, and your still more exacting king, we have something very like the economics of the Invasion of Anywhere in early feudal times.
Had the leaders of these invasions, or rather their clerkly secretaries, written the plain tale of their doings they would have left some such record as this: "There were we, a band of able-bodied, daring, needy men.

Our only trade was war; our only capital our suits of armour, our swords and battle-axes.

We heard that there was good land and rich booty to be had in Anywhere; we went and fought for it.

Our opponents were brave men, too, but badly organised.

In some places we won.