The Declaration of Independence was penned by a committee of representatives within the second Continental Congress. The entire Congress signed the final document after it went through several levels of editing and review.
Throughout the American Revolutionary War, the colonies slowly began to pull away from their ties with Great Britain. They formed their own congress, postal service, military, and currency. In June 1776, Richard Henry Lee suggested to the other members of congress that they should formally state their intention to establish an independent nation, and the concept for the declaration was born.
The purpose of the document was to indicate to Great Britain that they would no longer consider themselves under British rule. Furthermore, the document aimed to explain the many reasons that the colonies felt independence was their best, and only, choice. Among those reasons were the fact that Great Britain had failed to look out for the citizens in the colonies, and that they needed their own government to protect them.