Who is General Ulysses S. Grant

I was the leader of the Union Army.

Who is Abraham Lincoln?

I was the president of the United States and then president of the Union.

Who is Dread Scott?

I was a slave whose master died and I petitioned the Supreme Court to say I should be free because I had lived in two free states.

Who is Chief Justice Roger Taney?

I was a Supreme Court Justice who decided that Dread Scott was property and could not be free.