Engaging Islam

What was the proper approach to countering Islam in the late Middle Ages? If Islam was seen as a Christian heresy in accordance with a common medieval interpretation, the church’s battle against Muslims was seen in ad intra terms. If Islam was treated as a separate religion, an ad extra approach followed. In either case, would unity and peace be best achieved via negotiations or force, particularly around 1453 when Constantinople fell to Muslim forces? We begin with Nicholas of Cusa and Juan de Segovia, then turn to Tommaso Giustiniani and Vincenzo Querini in their Libellus and Leonem decem (1513). They pushed the Medici pope to counter Islam using language of the just war tradition because they saw Muslims as apostate Christians. Considering these three approaches side by side, we witness Christian leaders wrestling with religious, political, and military considerations in deciding how best to counter the Islamic advance during a crucial half-century.