"The chaos of Civil War meant only one thing to America's four million slaves: hope. With armies on the march, and the old social order crumbling, men like John Washington and Wallace Turnage seized the moment and made a break for freedom, issuing their own emancipation proclamations before the fact. They were 'quiet heroes of a war within the war to destroy slavery', as David W. Blight puts it in A Slave No More."
http://www.nytimes.com/2007/12/05/books/05grimes.html