Are you sure? How do you know?
Is it true that only two people signed the Declaration of Independence on July 4? They were John Hancock and Charles Thomson, right? What about reports that most of the rest signed on August 2, but the last signature wasn't added until 5 years later?
According to the historians at the National Archives, on July 2, 1776, twelve of the thirteen colonies approved a draft resolution for independence with New York finally agreeing on July 9. The draft was "Signed by Order and in Behalf of the Congress, John Hancock, President. Attest. Charles Thomson, Secretary."
However, that draft version isn’t the famous one you’ve seen. On July 19th, Congress ordered that the Declaration be "fairly engrossed on parchment” under a headline of “The unanimous declaration of the thirteen United States of America." That one was to be signed by every member of Congress, however, it took quite a while to get everybody’s signature for the printing and Pennsylvania’s Thomas McKean was the last person to sign. As a result, his signature doesn’t appear on some early copies.