Simplify the following text for a Grade 14 native English-speaking person.
Original: In 1765 , all of the colonies worked together for the first time unified political aim when the Stamp Act Congress ( meeting ) of representatives from across the Thirteen Colonies was held in New York City to write The Declaration of Rights and Grievances .
Simplified: At prelude to organized colonial opposition to British rule , the Stamp Act Congress of representatives from across the Thirteen Colonies was held in New York City in 1765 . The Congress resulted in the Declaration of Rights and Grievances , the first document by a representative body of multiple colonies to assert the concept popularly known as `` no taxation without representation '' .