Historic Flag
This flag is known as the "Rebel Stripes" flag, simply 7 red stripes and 6 white stripes alternating with no union or canton (an example of a union is the blue field with the 50 stars on it which is on today's flag). It is believed to be first used in 1765 as the Sons of Liberty flag, though that flag had only 9 vertical stripes. In the time between 1765 and 1777, the British union jack was added to the upper left and then removed, the stripes increased to 13 and the stripes became horizontal. In June of 1777, the congressional resolution of the United States flag mandated 13 alternating red and white stripes with a blue field in the left corner with 13 stars in it. Since this was only 4 months before the battle, most likely the solders would not have had the fabric or the time to add the blue field to the flag. Fort Mifflin in Delaware, which was under seize in October and November of 1777, also flew an adaptation of the rebel stripes flag during it's seize.