The Flag Act of 1818 established the colors of the flag, the number of stripes and a process for adding stars as states are added to the union, but there is no offical meaning behind the colors. However, when the official U.S. Seal was adopted in 1782, its colors were defined by Charles Thompson, Secretary of the Continental Congress: “The colors of the pales (the vertical stripes) are those used in the flag of the United States of America; White signifies purity and innocence, Red, hardiness & valour, and Blue, the color of the Chief (the broad band above the stripes) signifies vigilance, perseverance & justice.”
Who designed the first flag?
No one knows with absolute certainty who designed the first stars and stripes or who made it. Congressman Francis Hopkinson, who also worked on the Unites States Seal and other artistic projects, seems most likely to have designed it, and few historians believe that Betsy Ross, a Philadelphia seamstress, made the first one. That claim was first made by her descendants nearly 100 years after it was supposed to have occurred.