Which 1777 law established the original thirteen-stripe design of the United States flag?

The Flag Act of 1777 established the original thirteen-stripe design of the United States flag.

Passed by the Second Continental Congress on June 14, 1777, the measure specified thirteen alternating red and white stripes and thirteen white stars on a blue field. The stripes and stars represented the thirteen United States, the former British colonies that had declared independence. The resolution described the stars as representing “a new constellation.”

The brief law did not specify the flag’s exact dimensions, the arrangement of stars, or many manufacturing details. As a result, early American flags appeared in several patterns, including circular and row arrangements of stars. The popular story that Betsy Ross made the first flag is not established by contemporary evidence. Later laws changed the number of stars and, temporarily, the number of stripes. The Flag Act of 1818 restored thirteen stripes permanently and made the number of stars correspond to the number of states. June 14 is now observed as Flag Day.