What was the listeners background knowledge of mlk 'i had a dream' speech?

His listeners where both whites and blacks; Blacks had experienced the woes of Whiteman’s superiority ever since the Slave trade days but freed in 1863 when Abraham Lincoln signed into law the Proclamation Emancipation. Whites had witnessed police brutality against blacks and hated it. No wonder, they were in attendance here at Washington or had been following via the television.I had to do a speech analysis on this speech and this was part of the listerner background knowledge. Made and 100 so i know it right hope it helps 

Delegates officially ended the stamp act.