The U.S. was originally funded from the U.S. Treasury that embodied the U.S. Customs Service. The U.S. Customs Service collected duties on Imported Goods (primary source of income for the United States at that time). I'm not sure when the U.S. Treasury and U.S. Customs service came into being, i'm sure it's easy to look up.

Taxation of income from citizens was originally supposed to be a short term tax to help pay for the war efforts. Once taxation of the citizens started it was the beginning of being Tax Serfs to the government.

The U.S. Customs Service no longer collects duties on imported goods for the most part. (Free Trade)

There is no such thing as free trade. It has cost the American Citizens their livelyhood, Manufacturing base, Wealth, and Independence. We are now dependent on the rest of the world for our goods so therefore dependent on their good graces.