"Now we are engaged in a great civil war, testing whether that nation, or any nation so conceived and so dedicated, can long endure."
-- Abraham Lincoln, November 19, 1863, Gettysburg Address
A primary source is a document or physical object which was written or created during the time under study. These sources were present during an experience or time period and offer an inside view of a particular event. Some types of primary sources include:
The Purdue OWL site has excellent help for writing.