The vertical Sons of Liberty flag had nine stripes representing the nine protesting colonies that participated in the Stamp Act Congress of 1765. Its nine vertical red and white stripes were also symbolic of “45,” the number of the pamphlet published in 1763 by the English civil-rights activist John Wilkes, who influenced the American revolutionary movement. The symbolism of nine also applied to the nine states at the adoption of the Constitution on September 17, 1787.