The Aegean is again open to constant attack from Arab pirates.

A Muslim fleet of fifty-four large galleys manned by Muslim corsairs, led by the renegade Leo of Tripoli, and with the imperial capital of Constantinople as its initial target, sails from Syria, initially driving back the imperial navy under the droungarios Eustathios Argyros.

Eustathios is replaced by Himerios, about whose early life nothing is know.

He is the uncle of Zoe Karbonopsina, the mistress and later wife of Emperor Leo VI the Wise, and his career is the direct result of this relationship.

Initially a protasēkrētis, Himerios in 904 is appointed in command of the imperial fleet.

Himerios does not have to fight, however, as the Arabs withdraw on their own.

The two fleets encounter each other off Thasos, but the imperial navy chooses not to give battle.

As a result, the Arabs are able to turn to Thessalonica, the second city in the empire, totally surprising the imperial navy, which is unable to react in time.

The city walls, especially towards the sea, are in disrepair, while the city's two commanders issue conflicting orders.

After a short siege, the Saracens are able to storm the seaward walls, overcome the Thessalonians' resistance on July 29 and take the city.

The sacking continues for a full week, before the raiders depart for their bases in the Levant, having freed four thousand Muslim prisoners while capturing sixty ships, and gaining a large loot and twenty-two thousand captives, mostly young people.

In the event, most of the captives, including John Kaminiates, who will later chronicle the sack, will be ransomed by the Empire and exchanged for Muslim captives.

Aristocratic factions fight for control of the Bulgarian throne from 1257 until 1277.

Heavy taxation by feudal landlords causes their peasants to revolt in 1277 and enthrone the "swineherd tsar" Ivailo.

After 1300 Tatar control ends, and a new period of expansion follows under Mikhail Shishman (1323-1330) and Ivan Aleksandur (1331-1370).

As before, however, military and commercial success parallels internal disorder; the social chaos of the previous century continues to erode the power of Bulgarian leaders.

Meanwhile, Serbia has risen as a formidable rival in the Balkans, and the Ottoman Turks have advanced to the Aegean coast.

In the late fourteenth century, Bulgaria is weakened by the division of its military defenses between the two perceived threats.

Ivan Alexander succeeds the slain Tsar Mikhail Shishman.

As before, however, military and commercial successes parallel internal disorder.

Meanwhile, Serbia has risen as a formidable rival in the Balkans, and the Ottoman Turks have advanced to the Aegean coast.

Dushan subdues the sporadic revolts of the nobility, who had become more powerful during the period of civil wars, and in 1332 strengthens his alliance with the new Bulgarian emperor, Ivan Aleksandur, by marrying his sister Helen.

Eastern Southeast Europe (1360–1371 CE): Ottoman Expansion, Balkan Fragmentation, and Emerging Powers

Settlement and Migration Patterns

Ottoman Settlement and Administration

Between 1360 and 1371, the Ottoman Turks firmly established their dominance in the Balkans. Lands conquered by the Ottomans were systematically reorganized into feudal fiefs governed by cavalry officers. Local notables who converted to Islam participated actively in this new administration, facilitating Ottoman integration and consolidation throughout Thrace and southern Bulgaria.

Moldavian Expansion under Bogdan

In Moldavia, Bogdan of Cuhea, a Vlach voivode from Maramureş, solidified his rule following his successful rebellion against Hungarian authority. Establishing a new political center at Siret, he extended Moldavian territory northward to the Cheremosh River, reinforcing Moldavia’s independence from Hungarian suzerainty. Nonetheless, the southern Moldavian territories remained under the influence of the Tatar Mongols.

Political Dynamics and Regional Rivalries

Byzantine Vulnerability and Crusader Intervention

The Byzantine Empire remained vulnerable, exemplified by Emperor John V Palaiologos’ captivity by the Bulgarians. In 1366, responding to Pope Urban V's call, Amadeus VI, Count of Savoy, led a crusading force to aid Byzantium. Initially successful, Amadeus recaptured Gallipoli from the Turks and seized Black Sea ports including Mesembria and Sozopolis, later laying siege to Varna. Under pressure, Bulgarian Tsar Ivan Alexander released Emperor John V. However, atrocities committed by Catholic crusaders against local Orthodox populations significantly soured relationships, causing many Bulgarians to prefer Ottoman rule over alliances with the Latin West.

Fall of the Serbian Empire

Serbia experienced critical fragmentation following the death of childless Emperor Uroš the Weak in 1371. The absence of a legitimate heir led to the decentralization of power among regional magnates (velikaši), who assumed independent control over various provinces, adopting titles such as gospodin and despot. This fragmentation marked the definitive end of Serbia’s imperial unity, leaving the region vulnerable to Ottoman advances.

Economic and Technological Developments

Ottoman Administrative and Military Innovations

The Ottomans under Murad I (r. 1362–1389) institutionalized key imperial administrative structures. Positions such as the kaziasker (military judge), beylerbeyi (regional governor), and grand vizier (chief minister) were formalized, granted to non-dynastic officials to ensure efficient governance. Military innovations included the creation of the elite Janissary corps (Yeniçeri, "New Force"), recruited through the devshirme (child levy) system, and the establishment of the Kapikulu Corps ("Palace Guards"), modeled after earlier Seljuk and Abbasid traditions.

Cultural and Artistic Developments

Ottoman Urban and Religious Patronage

Ottoman ruler Orhan significantly contributed to cultural integration and Islamization in newly conquered areas. His construction of mosques, medreses (Islamic theological schools), and caravanserais across Anatolia and the Balkans facilitated the spread of Islamic culture and Ottoman urban life, marking the beginning of lasting architectural and cultural legacies in the region.

Serbian Cultural Fragmentation

As the Serbian Empire fragmented politically, its previously centralized cultural patronage dispersed among regional courts. Local Serbian rulers continued patronage of monasteries and religious art, albeit on a smaller and more localized scale, reflecting a broader cultural fragmentation accompanying political decentralization.

Social and Religious Developments

Religious and Ethnic Integration under Ottoman Rule

The Ottoman administrative system fostered religious and ethnic integration, encouraging conversion among local Balkan elites to Islam. This policy contributed to the development of a diverse yet structured Ottoman society, blending Islamic, Turkish, and Balkan Christian traditions.

Religious Tensions from Crusader Activity

The aggressive behavior of the Catholic crusaders, exemplified by the crusade of Amadeus VI, exacerbated existing religious tensions between Latin Christianity and Orthodox communities. The resulting animosity facilitated Ottoman expansion, as Orthodox populations increasingly viewed Ottoman rule as comparatively tolerable.

Long-Term Consequences and Historical Significance

The period from 1360 to 1371 CE marked a critical phase of Ottoman consolidation in Eastern Southeast Europe, the definitive fragmentation of the Serbian Empire, and the rise of independent Moldavia. These developments profoundly reshaped Balkan geopolitics, laying crucial foundations for long-term Ottoman dominance and significantly impacting regional cultural and religious identities.

John V is held captive by the Bulgarians, at this time.

Amadeus turns his forces against Bulgaria and captures the Black Sea ports of Mesembria and Sozopolis, then ...

...lays siege to Varna and sends Tsar Ivan Alexander an ultimatum to release John V or suffer further defeat.

Ivan Alexander releases John V and Amadeus returns to spend the winter in Mesembria, arriving there with John V before Christmas.

The regency for John V Palaiologos, paying the price for Ivan Alexander of Bulgaria's support in the civil war of 1341–47, had surrendered Phillipopolis and eight other cities in 1344 after holding them for twenty years.

The Ottoman Turks under Lala Shahin Pasha in 1364 move through the Maritsa River valleys and seize Philippopolis, calling the city Filibe, a corruption of "Philip".

It will be the capital of Rumelia until 1382, when the Ottomans capture Sofia, which is to become the main city of the province.

Plovdiv survives as one of the major cultural centers for Bulgarian culture and tradition.

Control of the main sources of Constantinople's grain and tax revenues enables Murad to force the emperor in Constantinople to accept Ottoman suzerainty.

Urban had in May 1363 made an appeal to Louis I of Hungary for a crusade against the Turks, and the king has spent the winter of 1364–65 preparing an army for a major offensive designed to push the Turks out of Europe.

In January 1365, as reported at Venice, ten galleys were being gathered in Provence for Louis's use, and Louis had issued a call for support in Zadar (Zara) and Dalmatia.

In the spring he invades, not Turkish Europe (Rumelia), but rather the north of Bulgaria, at this time ruled by the tsar's second son, Sratsimir.

He conquers and occupies Vidin, and takes Sratsimir captive back to Hungary.

His expedition is thus completed in time for him to cooperate with Amadeus of Savoy in a joint attack on the Turks in the spring of 1366.