In Mehmed II's first reign, he defeated the crusade led by John Hunyadi after the Hungarian incursions into his country broke the conditions of the truce per the Treaties of Edirne and Szeged.

During Mehmed II's first reign, he defeated the crusade led by John Hunyadi after the Hungarian incursions into his country broke the conditions of the truce per the Treaties of Edirne and Szeged in September 1444.

[15] In 1453, Mehmed commenced the siege of Constantinople with an army between 80,000 and 200,000 troops, an artillery train of over seventy large field pieces,[16] and a navy of 320 vessels, the bulk of them transports and storeships.

Before the city could be taken, intelligence was received about an approaching Hungarian relief force led by Hunyadi, which caused Mehmed to lift the siege and start marching back to his domains.

[35] By August the campaign was effectively over,[32] Mehmed left a part of his force under the command of Firuz Bey in Serbia in anticipation of a possible offensive on Ottoman territories by Hunyadi.

[34] Following the conquest of the city, Mehmed captured various other Serbian settlements in the surrounding area,[33] after which he started his march back towards Edirne, visiting his ancestor Murad I's grave in Kosovo on the way.

Significant preparations were made by the Sultan for the conquest of the city, including the casting of 22 large cannons alongside many smaller ones and the establishment of a navy which would sail up the Danube to aid the army during the siege.

Turahanoğlu Ömer Bey, who served with distinction and wiped out a force of 6,000 Wallachians and deposited 2,000 of their heads at the feet of Mehmed II, was also reinstated, as a reward, in his old gubernatorial post in Thessaly.

According to the Byzantine historian Michael Critobulus, hostilities broke out after an Albanian slave of the Ottoman commander of Athens fled to the Venetian fortress of Coron (Koroni) with 100,000 silver aspers from his master's treasure.

[62] Using this as a pretext in November 1462, the Ottoman commander in central Greece, Turahanoğlu Ömer Bey, attacked and nearly succeeded in taking the strategically important Venetian fortress of Lepanto (Nafpaktos).

[62] The new alliance launched a two-pronged offensive against the Ottomans: a Venetian army, under the Captain General of the Sea Alvise Loredan, landed in the Morea, while Matthias Corvinus invaded Bosnia.

Small-scale warfare continued on both sides, with raids and counter-raids, but a shortage of manpower and money meant that the Venetians remained largely confined to their fortified bases, while Ömer Bey's army roamed the countryside.

[75] After Skanderbeg died, some Venetian-controlled northern Albanian garrisons continued to hold territories coveted by the Ottomans, such as Žabljak Crnojevića, Drisht, Lezhë, and Shkodra – the most significant.

[81][better source needed] Uniting the Anatolian beyliks was first accomplished by Sultan Bayezid I, more than fifty years before Mehmed II but after the destructive Battle of Ankara in 1402, the newly formed unification was gone.

In 1456, Peter III Aaron agreed to pay the Ottomans an annual tribute of 2,000 gold ducats to ensure his southern borders, thus becoming the first Moldavian ruler to accept the Turkish demands.

The Moldavian army was utterly defeated (casualties were very high on both sides), and the chronicles say that the entire battlefield was covered with the bones of the dead, a probable source for the toponym (Valea Albă is Romanian and Akdere Turkish for "The White Valley").

This strategically sited fortress, at the lowlands near the end of the old Via Egnatia, cut Albania effectively in half, isolating Skanderbeg's base in the northern highlands from the Venetian holdings in the south.

After conquering Constantinople, when Mehmed II finally entered the city through what is now known as the Topkapi Gate, he immediately rode his horse to the Hagia Sophia, where he ordered the building to be protected.

Building projects were commenced immediately after the conquest, which included the repair of the walls, construction of the citadel, a remarkable hospital with students and medical staff, a large cultural complex, two sets of barracks for the janissaries, a tophane gun foundry outside Galata, and a new palace.

[97] This measure apparently had no great success, since French voyager Pierre Gilles wrote in the middle of the 16th century that the Greek population of Constantinople was unable to name any of the ancient Byzantine churches that had been transformed into mosques or abandoned.

He gathered Italian artists, humanists and Greek scholars at his court, allowed the Byzantine Church to continue functioning, ordered the patriarch Gennadius to translate Christian doctrine into Turkish, and called Gentile Bellini from Venice to paint his portrait[102] as well as Venetian frescoes that are vanished today.

After his conquest of Bosnia in 1463, he issued the Ahdname of Milodraž to the Bosnian Franciscans, granting them the freedom to move freely within the Empire, offer worship in their churches and monasteries, and practice their religion free from official and unofficial persecution, insult, or disturbance.

Mehmed the Conqueror transitioned the empire away from the Ghazi mentality that emphasizes ancient traditions and ceremonies in governance[108] and moved it towards a centralized bureaucracy largely made of officials of devşirme background.

[108] This centralization was possible and formalized through a kanunname, issued during 1477–1481, which for the first time listed the chief officials in the Ottoman government, their roles and responsibilities, salaries, protocol and punishments, as well as how they related to each other and the sultan.

[114][failed verification] Aside from his efforts to expand Ottoman dominion throughout the Eastern Mediterranean, Mehmed II also cultivated a large collection of Western art and literature, many of which were produced by Renaissance artists.

From a young age, Mehmed had shown interest in Renaissance art and Classical literature and histories, with his school books having caricaturistic illustrations of ancient coins and portraiture sketched in distinctly European styles.

This interest culminated in Mehmed's work on building a massive multilingual library that contained over 8000 manuscripts in Persian, Ottoman Turkish, Arabic, Latin, and Greek, among other languages.

[118][119] Additionally, his commissioning of Renaissance artwork was, itself, possibly an attempt to break down Western-Oriental cultural binaries in order for Mehmed to present himself as a Western-oriented ruler, among the ranks of contemporary European Christian monarchs.

His social circle included a number of humanists and sages such as Ciriaco de' Pizzicolli of Ancona, Benedetto Dei of Florence and Michael Critobulus of Imbros,[114] who mentions Mehmed as a Philhellene thanks to his interest in Grecian antiquities and relics.

Mehmed's thirty-year rule and numerous wars expanded the Ottoman Empire to include Constantinople, the Turkish kingdoms and territories of Asia Minor, Bosnia, Serbia, and Albania.