On July 28, 1480, Òtranto was surprised by a massive Ottoman fleet. 150 vessels carrying cavalry, 18,000 professional soldiers, and previously unseen weapons such as muskets, artillery, and bombards. The 6,000 inhabitants of Òtranto had no defenses, and the few guards made the fatal mistake of killing the enemy ambassador who had come to negotiate a surrender. On August 11, under the command of Ahmet Pasha, the Turks entered as conquerors. Subsequent accounts narrate incredible cruelties. Bishop Stefano Agricoli was beheaded in the cathedral, the last defense, along with the entire clergy and the population seeking refuge.

On August 12, 800 surviving adult men were beheaded on the hill of Minerva. Tradition tells of martyrdom, following the demand for conversion to Islam, but it's more likely that Ahmet's cruelty had no religious motivations.

In any case, the inevitable question is: why such ferocity, and why against Òtranto? Before attempting an explanation, other matters need to be clarified.

The first thing to note is that immediately after the disaster, the Kingdom of Naples under Ferdinand I of Aragon, who then ruled over Salènto, sought help from the mighty Venice. Theoretically, Venice was a Christian power and more pragmatically interested in trading in the port of Otranto. However, the Serenissima refused. They had only to gain from a weakening of the Kingdom of Naples. What's more, Venice, after an exhausting war with the Turks, had just concluded a non-belligerence agreement with Mehmed II a year earlier. It was a heavy peace for the Venetians, essentially accepting that they were no longer the sole masters of the Adriatic. However, pragmatism had made Venice great, and that agreement allowed their economy to recover.

Without Venice, Ferdinand's son, Duke Alfonso of Aragon, tried to retake Òtranto with a pincer maneuver, from land and sea, but it wasn't sufficient. Frustrated, he managed to extract a promise of help from Pope Sixtus IV. Even other Italian states, led by Milan and Florence, joined in - but only on paper. In reality, internal conflicts among the bickering Italians mattered more than the Pope's appeal. After a year, the Ottomans had not only rebuilt the damaged walls but were advancing in the north of Salènto. An unexpected event stopped them: the death of Mehmed II, which forced Ahmet Pasha to return home. Neapolitan spies intercepted him in Valona and managed to destroy his fleet. On September 10, 1481, the last 2,000 Turks in Òtranto, now devoid of resources, surrendered, ending the Turkish occupation.

From a military history perspective, it's interesting to note that Alfonso of Aragon's strategies in 1481, though unsuccessful, were innovative: the destruction of Turkish supply infrastructure and the gradual use of troops. Today, it's called "war of attrition." It was in the defense, the previous year, that the Aragonese had gone wrong in every way: they had convinced themselves that recently invented firearms were just a passing fad. Their defenses in southern Italy, quite solid until 1300, hadn't been updated.

After that event, everything changed: the Aragonese decided not to repair even the medieval fortifications but rather to rebuild them from scratch. The Aragonese Castle that can be visited today is the result of the efforts throughout the 16th century to come to terms with the ongoing evolution of firearms.

With all this, we haven't yet answered why the Turks targeted Òtranto. If the Italian states' geopolitical objective was to weaken each other, the Ottoman sultans had a more ambitious one: to conquer the territories that once belonged to the Roman Empire. Or rather, to reclaim them, as Mehmed II considered the Holy Roman Empire illegitimate. To him, the natural heir of the Caesars was the Eastern Roman Empire. Now, having taken Constantinople, the capital of the Eastern Empire, in 1453, it's clear that from their perspective, the Sultan was the heir of Rome. In fact, among the titles that Mehmed II attributed to himself was Kaiser I Rum, Caesar of Rome. The conquest of southern Italy fully fit into this imperial program. 

The Ottomans dominated, absorbed, and didn't impose religious conversion on their Christian and Jewish subjects.

The capture of Òtranto then, should not be considered an act of piracy, much less a religious war. It is rather an episode in the conquest strategy of an imperial ideology.