[8] He is the Director of the Crusades Studies Forum and the Medieval Italy Prosopographical Database Project, both housed at Saint Louis University.

Madden has books and articles including the "Crusades" entry for the Encyclopædia Britannica.

His 1997 revision of The Fourth Crusade: The Conquest of Constantinople (originally authored by Donald Queller) was a selection of the History Book Club.

[10][11] According to the Medieval Review, with this book "Madden more than ever stakes out his place as one of the most important medievalists in America at present.

In the case of Rome, he argued that their citizens and leaders acquired a level of trust among allies and potential enemies that was based upon an unusual rejection of hegemonic power.