They were doctors, lawyers, farmers, and in some cases, "gentlemen" (meaning they had land and no "occupation"). Some of them were highly educated, but some were barely able to write. Some were strongly in favor of independence from Great Britain. Some were fiercely loyal to His Majesty, King George. But they all knew that by signing the document, they were committing treason.
And yet, they did it. They signed, and began the "great experiment" of freedom. It was truly a revolutionary thought for the time: to have a colony or colonies separate themselves from the mother country. But due to the oppressive tyranny of King George, and the myriad of taxes and other intrusions impressed upon the Colonies by the English Parliament, they had to commit this act of treason.
Today, as we celebrate the adoption of the Declaration of Independence, let us not forget that sacrifice that those men made, for they truly gave of themselves, their lives, and their sacred honor.