Primary Sources

http://avalon.law.yale.edu/subject_menus/19th.asp

AWESOME Primary Sources Site.
They have everything organized from Ancient History through the 21st century, including 5 states' secession letters in the Civil War, tons of treaties, the Athenian Constitution (from back in the day...Ancient History time), and treaties from the 16th century.

 It could be interesting to have students compare treaties of the 20th century versus the 16th century. Bet that hits a Common Core Standard (Primary sources, comparisons, perspective, whichever you are looking to cover)!