How did Monarch's make money in medieval Europe?

The reason there was no income tax is because most people didn't have an income, they lived simply to survive and rarely worked for a wage. Tenants paid rent and often borrowed the seeds they planted paying back real money when they sold their crop. Landlords (yes that is where we get the name from) owned the land, took the rent and in turn paid their dues to the crown...if they wanted to keep their land. The 'spoils of war' often covered the cost...soldiers worked for nothing and stole what they could from the enemy... but the enemies castle and land became the triumphant kings own property and he used it as he saw fit.