Final answer:
The Stamp Act of 1765 was the first direct tax by Parliament on the American colonies, uniting them in opposition to British policy and spawning the Stamp Act Congress which drafted a declaration against taxation without representation.
Step-by-step explanation:
The first direct tax by Parliament on the American colonies was the Stamp Act of 1765. This act became a catalyst that united the colonies against King George and the British Parliament's policy of 'taxation without representation'. It levied a tax on various documents and printed materials used in the colonies, including newspapers, pamphlets, and legal documents. In response, the Massachusetts Assembly initiated a unified protest by sending out letters to other colonies, leading to the convening of the Stamp Act Congress in New York.
This gathering of representatives from nine colonial legislatures drafted the Declaration of Rights and Grievances, expressing their opposition to the Stamp Act and the concept of taxation without representation.