Answer: The monarchs taxed some people because taxation has always been the main source of income for any political regime.
Step-by-step explanation:
Monarchies were not the exception, and monarchs needed resources for keeping armies, paying some government officials, and obtaining their private wealth. These resources came mainly from earnings from trade with other states, the printing of coins (seignorage), and taxes. Taxes were the primary source, and they could be charged in monetary value or physical goods.