Frederick Douglass, who was the first African American to receive a vote for President of the United States in a major party's roll call vote. That was at the 1888 Republican National Convention.
Born a slave, he escaped to freedom in the North and became a well-respected speaker, writer, reformer and statesman. As Wikipedia explains, "He stood as a living counter-example to slaveholders' arguments that slaves did not have the intellectual capacity to function as independent American citizens."
“I am a Republican, a black, dyed in the wool Republican, and I never intend to belong to any other party than the party of freedom and progress."
“I didn't know I was a slave until I found out I couldn't do the things I wanted.”
“The limits of tyrants are prescribed by the endurance of those whom they oppose.”
“If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning.”
“People might not get all they work for in this world, but they must certainly work for all they get.”
“Where justice is denied, where poverty is enforced, where ignorance prevails, and where any one class is made to feel that society is an organized conspiracy to oppress, rob and degrade them, neither persons nor property will be safe.”
“The thing worse than rebellion is the thing that causes rebellion.”
“A little learning, indeed, may be a dangerous thing, but the want of learning is a calamity to any people.”
“I prefer to be true to myself, even at the hazard of incurring the ridicule of others, rather than to be false, and to incur my own abhorrence.”
“The life of a nation is secure only while the nation is honest, truthful, and virtuous.”
“I recognize the Republican party as the sheet anchor of the colored man's political hopes and the ark of his safety.”
“Find out just what any people will quietly submit to and you have the exact measure of the injustice and wrong which will be imposed on them.”
“To suppress free speech is a double wrong. It violates the rights of the hearer as well as those of the speaker.”
“The soul that is within me no man can degrade.”