Mehmed II, after turning his attentions eastward to clean up the remnants of imperial Greek rule in 1461, had been faced with the growing power of the Ak Koyunlu, whose leader, Uzun Hasan, had continued the tradition of close relations between the imperial throne and his own kingdom.

As a consequence, he had supported the Empire of Trebizond and sent them military aid, but his support wasn't enough to save Trebizond from the Ottoman forces.

After Mehmed II conquered all of the Eastern Black Sea region, Uzun Hasan, fearing that the Ottomans would return to take his own principality, had decided to seek help from Christian powers, and had signed a treaty with the Republic of Venice, who are menaced in the Aegean Sea by the expanding Turkish presence.

Another reason for tensions between the Ak Koyunlu and the Ottomans is the political standing of the Karamanids, the most powerful Turkish beylik in Anatolia.

İbrahim Bey, the ruler of Karamanids, had supported the growing power of Uzun Hasan.

When İbrahim Bey died in 1464, his son Pir Ahmet had tried to ascend the throne, but his half brother İshak Bey, who was the legal heir, had become the bey with the support of Uzun Hasan.

Nevertheless, Pir Ahmet had not given up and had requested the support of Mehmet I, offering a part of his beylik in return With Ottoman support he had defeated his brother in the battle of Dağpazarı.

İshak escaped to Silifke, the southern frontier of the beylik, and Pir Ahmet assumed the title bey.

Keeping his promise to the sultan, he had ceded a part of the beylik to the Ottomans, but was uneasy about the loss of these lands, so during the Ottoman campaign to the west, he had retaken his former territory.

However, Mehmet had responded by capturing both Karaman (Larende) and Konya, two major cities of the beylik, in 1466.

Pir Ahmet, together with his brother Kasım, had made a narrow escape to Uzun Hasan's territory.

A few years later, Ottoman vizier Gedik Ahmet Pasha had captured the coastal region of the beylik.

This had given Uzun Hasan a chance to interfere.

In 1472, the Ak Koyunlu army had invaded and raided much of Anatolia.

With Akkoyunlu help, Pir Ahmet had captured Karaman, but almost immediately afterward, Mehmed II returns with his army in 1473 to defeat Uzun Hasan.

The Turkemens have a traditional army with considerable numbers of light cavalry, whereas the Ottoman army, equipped with the latest technology, arrives with matchlock arms and cannons.

The Ottomans gain a decisive victory over the Turkmens, whose army is nearly destroyed in eight hours of fighting.

Uzun Hasan, after receiving the decapitated head of one of his sons, flees the battlefield.

The forced withdrawal of the decimated Ak Koyunlu army leaves Mehmed in control of all Anatolia, and Venice without a powerful ally.

It also brings the Ottomans into conflict with the Mamluk empire of Syria and Egypt, which seeks to expand into southeastern Anatolia.

Pir Ahmet attempts to continue his struggle, but when he learns that his family members have been transferred to Constantinople by Gedik Ahmet Pasha, he finally gives up the fight.

Demoralized, he escapes to Akkoyunlu territory, where he is given a tımar (fief) in Bayburt.

Prince Isaac of Theodroro, the final rump state of the Eastern Roman Empire, had engaged in a rapprochement with the Genoese at Caffa in the face of the mounting Ottoman danger, and has wed his sister Maria Asanina Palaiologina to Stephen the Great, ruler of Moldavia.

His increasingly pro-Ottoman stance in later years, however, leads to his overthrow by his brother Alexander, with Stephen’s backing.

This comes too late to save Theodoro: Gedik Ahmed Pasha, who also fought against Venetians in the Mediterranean, is dispatched in 1475 by the Sultan to aid the Crimean Khanate against Genoese forces.

He conquers Caffa, Soldaia, Cembalo and other Genoese castles as well as the Principality of Theodoro, after a three-month siege of its capital, Mangup.

Alexander and his family are taken captive to Constantinople, where the prince is beheaded, his son is forcibly converted to Islam, and his wife and daughters become part of the Sultan's harem.

Gedik Ahmed Pasha also rescues the Khan of Crimea, Meñli I Giray, from Genoese forces.

As a result of this campaign, Crimea and Circassia enter into the Ottoman sphere of influence.

Kasım has allied himself with Republic of Venice, and with the help of Venetian navy, he had briefly been able to keep Silifke and the Mediterranean coast of the beylik.

However, following the campaigns of Gedik Ahmed Pasha of the Ottoman Empire, he loses all of his possessions in 1475.

The Knights of St. John, with their headquarters at Rhodes, hold the island as a bar to Ottoman expansion in the Aegean.

Pierre d'Aubusson, a son of French nobility who joined the Knights around 1453, had become grand master of the order in 1476.

The island of Tilos (located between Rhodes and another island, Kos) had been evacuated to Rhodes in 1470 because they were susceptible to attacks from the Ottoman Empire.

The island of Chalki (six kilometers west of Rhodes, the smallest inhabited island of the Dodecanese) had also been evacuated to Rhodes in 1475 for the same reason.

An Ottoman fleet of one hundred and sixty ships appears on May 23, 1480, before Rhodes, at the gulf of Trianda, along with an army of seventy thousand men under the command of Gedik Ahmed Pasha or Mesih Pasha.The Knights Hospitaller garrison is led by d'Aubusson.

The Knights are reinforced from France by five hundred knights and two thousand soldiers under d'Aubusson's brother Antoine.

The Ottomans' first strategic goal is to capture the Tower of St Nicholas, which is the knights' key point in the defense of the two harbors: the commercial, Mandraki, and the one to the east bay of Akandia.

The Turkish artillery keeps up an unbroken bombardment and on June 9 the infantry makes a series of attacks.

Grand Master d'Aubusson himself speeds to the aid of the garrison and after a fierce struggle the enemy is repelled.

Shortly after comes a second attack on the tower, this time on the eastern sector of the wall towards the bay of Akandia, which is the battle station of the "tongue" of Italy and is quite weak.

During the bombardment from the Turkish artillery, the Knights and the people meanwhile dig a new moat on the inside of the wall at this point and construct a new internal fortification.

Once again the Knights react valiantly and decisively and after a bitter battle with many casualties on both sides, the danger is once more averted.

The Turks at dawn on July 27, launch a vigorous offensive on the Jewish quarter of the city, and their vanguard of around twenty-five hundred Janissaries manages to take the tower of Italy and enter the city.

A frenzied struggle ensues.

The grand master, wounded in five places, directs the battle and fights with lance in hand.

After three hours of fighting the enemy are decimated and the exhausted survivors begin to withdraw.

The Knights’ counterattack causes the Turks to beat a disorderly retreat, dragging along with them the Vizier and commander-in-chief.

The Hospitallers reach as far as his tent and take, along with other booty, the holy standard of Islam.

On this day between three and four thousand Turks are slain.

The Ottoman fleet on August 17, 1480, abandon their attempt to capture Rhodes.

Sultan Mehmed II is furious and would have attacked the island again, but his death in 1481 will put a stop to the attempt.

The French knight Guillaume Caoursin, vice-chancellor of the Knights Hospitaller, fought in the siege of Rhodes and writes its description in his Obsidionis Rhodiae Urbis Descriptio (an English translation exists as a part of Edward Gibbon's Crusades).

D'Aubusson's own report on the siege can be found in John Taaffe's history of the Holy, military, sovereign order of st. John of Jerusalem.

D'Aubusson gains widespread fame in Europe for his successful defense of the island.

A force of nearly twenty thousand Ottoman Turks under the command of Gedik Ahmed Pasha invades southern Italy in the summer of 1480.

The first part of the plan is to capture the port city of Otranto.

After it falls, its garrison and inhabitants are executed or sold into slavery.

In response, Pope Sixtus IV issues his second call for a Crusade.

In August 1480, seventy ships of the fleet attack Vieste.

On September 12, the Monastero di San Nicholas di Casole, which accommodates one of the richer libraries of Europe, is destroyed.

Between August and September 1480, King Ferdinand of Naples, with the help of his cousin Ferdinand the Catholic and the Kingdom of Sicily, tries unsuccessfully to recapture Otranto.

By October, attacks have been conducted against the coastal cities of Lecce, Taranto and Brindisi.

However, due to lack of supplies, Gedik Ahmed Pasha does not consolidate his force's advance.

Instead he returns with most of his troops to Albania leaving a garrison of eight hundred infantry and five hundred cavalry behind to defend Otranto.

It is assumed he will return with his army after the winter.

Meanwhile, several Christian monarchs are responding to the papal call with military support.