The following links come primarily from the Yale Center for International and Area Studies and focus on the Religious Riots which took place in Philadelphia in 1844.
American Nativism 1830-1845
Chronology of Nativism
The Riots of 1844
Philadelphia Bible Riots - an article
When Christians Killed Each Other Over Religion in Public Schools
An article with a modern perspective.
I Know Nothing
Anti-Catholicism and the Know-Nothings