The notion of Reconquista is the product of 19th-century Spanish Nationalist thinking. Although developed as an academic concept, it played, at the same time, a crucial political and ideological role, thus holding a very powerful and potentially toxic ideological burden, chiefly consisting of the idea that Spain is a nation shaped against Islam. Its dual academic and ideological nature makes it a highly problematic concept that greatly contributed to produce a largely biased and distorted vision of the Iberian medieval past, aimed at delegitimizing the Islamic presence (al-Andalus) and therefore at legitimizing the Christian conquest of the Muslim territory. Over the last years and in the framework of the Clash of Civilizations doctrine, conservative and far-right scholarly and political outlets reignited the most ideological version of the Reconquista, thus raising a major challenge for academic historians.