The reason why the United States economy became more reliant on money in the late 1800's because of the Civil War. The U.S needed to pay for the expenses of transporting soldiers, feeding them, and etc. Going to war is not free, and it is a very hefty price when a country goes to war. Because of this, the United States started to compose what is now called "income tax." The income taxed made citizens pay to help fund the war. After the war, they also needed money to rebuild the South.
Slaves in Rome might include prisoners of war, sailors captured and sold by pirates, or slaves bought outside Roman territory. In hard times, it was not uncommon for desperate Roman citizens to raise money by selling their children into slavery.
The federal government was the George Washington in convention
