Final answer:
The Intolerable Acts led to the calling of the first Continental Congress as a response to British punitive measures against the colonies, particularly after the Boston Tea Party.
Step-by-step explanation:
The event that most directly led to the calling of the first Continental Congress was the Intolerable Acts. In response to the Boston Tea Party, the British Parliament passed a series of punitive measures known as the Coercive Acts, which the colonists termed the Intolerable Acts. These acts closed Boston's harbor, limited colonial assemblies, and required colonists to quarter British soldiers. The oppressive nature of these acts united the colonies in opposition to British rule, prompting the assembly of the First Continental Congress in September 1774.
The Congress aimed to address these grievances by approving the Declaration of Rights and Grievances and forming the Continental Association to enforce boycotts against British goods.