Well 1861/62 saw the first Revenue Act to tax income.  But a careful read shows it applied only to federal things, soldiers, officer pay, etc.  Basically Congress taxing Congress' stuff.  But yes, the introduction of FRNs allowed the banksters (in partnership with government) to apply federal taxation out to the rest of America.  But it was a very slow, gradual process.  Remember, the early FRNs were backed by metal, real money, and were probably considered placeholders for money, not money itself.  Says right on them: "PAY TO THE BEARER ON DEMAND...TEN DOLLARS."