Final answer:
William Pitt used principles in his speech that were reflected in the Declaratory Act of 1766, asserting British Parliament's authority over the American colonies and nullifying any colonial laws that opposed parliamentary legislation.
Step-by-step explanation:
In his speech about the Stamp Act, William Pitt referred to principles that were later encapsulated in the Declaratory Act of 1766. The Declaratory Act was passed by Parliament to assert its authority over the colonies by stating that all laws passed in the colonies were void if they contradicted the laws of Parliament. This assertion followed the repealing of the Stamp Act, which had imposed a direct tax on the colonists for printed materials such as newspapers, legal documents, and playing cards. The colonists celebrated the repeal of the Stamp Act, but the introduction of the Declaratory Act and subsequent taxes like the Townshend Acts created new tensions between the colonies and Great Britain. Pitt's views during this period were aligned with colonial concerns about parliamentary taxation without representation and the need for colonial voices to be heard in British governance.