Yes, they did. Prior to 1776 as well. It was internationally known.
In answer to this objection, it may be asked, where did this infamous commerce originate? Where is it still carried on with all the eagerness which avarice can inspire? Where, but in England? By what means can it be abolished? Surely by that power alone, which America acknowledges the parent state, may justly exercise over all her dominions, viz. the power of regulating their trade. The legislatures of some of the colonies have done what they could to put a stop to the importation of African slaves, by loading it with the heaviest duties: And others have attempted the total abolition of it, by acts of assembly which their governors refused to pass.
You can read it, or you can listen to it. But its time for you to drop the act. No more theatrics. Give the Founding Fathers what the Founding Fathers are due.
They were absolutely *NOT* concerned about slavery when their representatives signed the Declaration of Independence.
They were *ONLY* concerned about the right to leave the Union and form their own government. (A Confederacy.)
Again, I will say linking slavery to the Declaration of Independence in 1776 is dishonest.
It wasn't about slavery, it was about *INDEPENDENCE*.