Final answer:
The end of Quaker dominance in the Pennsylvania legislature was marked by the ratification of the U.S. Constitution. This event, along with the restructuring of government post-American Revolutionary War, led to political changes that reduced Quaker influence in the state's government.
Step-by-step explanation:
The event that marked the end of Quaker dominance in the Pennsylvania legislature was the ratification of the U.S. Constitution (Option 2). This was a pivotal moment in history as the Confederation government was phased out and a new structure of governance was introduced, which reshaped political power and influence in the state of Pennsylvania. The Constitutional Convention held in Philadelphia saw the composition of a new federal government and subsequently, the Pennsylvania constitution was revised to align with the new national framework, diminishing the Quakers' stronghold on the legislative process. This shift reflected changes after the end of the American Revolutionary War, as established by the Treaty of Paris which brought an official end to the conflict. Following the ratification of the Constitution, there were significant social, economic, and political changes that collectively reduced the Quakers' control over Pennsylvania’s legislature.