This act was passed to assert the authority of the British government to tax its subjects in North America after it repealed the much-hated Stamp Act. The purpose of the Declaratory Act of 1766 was to affirm that Great Britain had complete authority to tax its American colonies.In general the act is descryibed simply as a theoretical gesture or political tactic to ease the passage of the Stamp Act. The famous quote "No Taxation Without Representation" was created in response to The Stamp Act. Learn about John Adams' involvement in the protests. The purpose of the tax was to pay for British military troops stationed in the American colonies after the French and Indian War. On March 18, 1766, George III approved Parliament's repeal of the Stamp Act and its passage of the Declaratory Act. The repeal of the Stamp Act did not mean that Great Britain was surrendering any control over its colonies. British Parliament ultimately voted 276-168 to repeal the Stamp Act on March 18, 1766. Complete image credits at americainclass.