As Pope Sixtus IV (born Francesco della Rovere) began his papal reign, he made clear his intention to renew the crusade against the Ottoman Turks. Despite initial successes by Pope Sixtus IV in such religiously-motivated efforts as the military expeditions against the Turks in Smyrna, his attempts at evangelism in Turkic territory and at unification of the Church in Europe failed entirely. Thus, throughout the majority of his reign, Pope Sixtus IV invested in cultural and political ventures that would help to strengthen his position as Pope. He surrounded himself with relatives and friends, building on the prestige of his familial line through nepotistic practices, while involving himself in a number of scandalous practices. From endorsing his nephews’ plot to overthrow the Medici, to inciting Venetian aggression against the duchy of Ferrara, Pope Sixtus IV paved a path of corruption that would consume the reign of future popes. (Image Source: Melozzo da Forlì [Public Domain], via Wikimedia Commons, https://commons.wikimedia.org/w/index.php?curid=155449)