1833The village of Chicago was incorporated one year after the Black Hawk War, which ended the last armed Native American resistance in the area. Four years later, Chicago was incorporated as a city after its population reached 4,000.1861The federal government, strapped for cash to fight the Civil War, levied the first federal income tax. The tax was 3% of all income that exceeded $800. Congress repealed the law in 1871, but in 1909 passed the 16th Amendment, which was ratified in 1913.