Ancient Mesopotamian households paid taxes in kind rather than money, and paid different taxes throughout the year, including poll taxes of livestock. Merchants transporting goods paid tolls and duties. The most burdensome tax was a labor obligation where free men owed months of service to the government doing tasks like harvesting or military service. Men avoided this by substituting slaves or hired workers, though this was technically illegal. Cuneiform tablets provide insights into Mesopotamian taxation systems.