The doctrine of equality had been developed in Europe without special reference to questions of distinct race or color.

But the terms, which are universal and as broad as humanity in their denotation, came to be applied to black men as well as to white men.

Massachusetts embodied in her state constitution in 1780 the words, "All men are born free and equal," and the courts ruled that these words in the state constitution had the effect of liberating the slaves and of giving to them the same rights as other citizens.

This is a perfectly logical application of the doctrine of the Revolution.
The African slave-trade, however, developed earlier than the doctrine of the Declaration of Independence.

Negro slavery had long been an established institution in all the American colonies.