Post-classical history

Nicaea, Empire of

One of the three Greek successor states of the Byzantine Empire that emerged after the conquest of Constantinople by the Fourth Crusade (1202-1204) in April 1204.

The empire took its name from its capital, Nicaea (mod. Iznik, Turkey), a city in the northwestern corner of Asia Minor. Nicaea, the venue of two ecumenical synods (325 and 787), had come under Turkish rule in the late eleventh century and formed the first capital of the Saljûq sultanate of Rûm until 1097, when it was captured by the First Crusade (1096-1099) and handed over to the Byzantine emperor. The Empire of Nicaea was established by the first Byzantine emperor-in-exile, Theodore I Laskaris, who was recognized by the local Greeks in Asia Minor as “emperor of the Romans” as early as autumn 1204. He was crowned emperor in Nicaea only in 1208, shortly after the election of the first ecumenical patriarch-in-exile. Nicaea remained the capital until the recovery of Constantinople from the Latins in 1261, although the later emperors used Nymphaion (mod. Kemalpaşa, Turkey) as their principal residence.

On the death of Theodore I Laskaris (1222), he was succeeded in turn by his son-in-law John III Vatatzes and by John’s son Theodore II (1254). The last emperor, Michael VIII Palaiologos, usurped the throne from Theodore II’s son John IV, then still a child, in 1258. At the peak of its power, the empire extended from the Black Sea coast to southwestern Asia Minor and from eastern Thrace to the Dalmatian coast in the Balkans.

The first conflicts between the Greeks of the Empire of Nicaea and the Latins of the new Empire of Constantinople took place in northwestern Asia Minor in autumn 1204. In December 1204, at Poimanenon, the forces of Nicaea suffered a crushing defeat at the hands of the Latins. In the spring of 1205, northwestern Asia Minor again came under fierce attack, but in April the Latin army was recalled to the European side of the Bosporus to repel the army of the Bulgarian tsar Kalojan (Johannitsa). It was this diverson and the subsequent defeat of the Latins at the battle of Adrianople (April 1205) that saved the Greek towns in Asia Minor from falling to the Latins and offered the forces of Nicaea the opportunity to regroup. In the following years, the Latins captured a number of towns in Asia Minor, in spite of the resistance of the local Greeks under Theodore I. In 1212, after a successful expedition in Asia Minor, the Latin emperor Henry concluded a treaty with Theodore I at Nymphaion, offering him territories that had never previously been under Nicaean control. Until Theodore I’s death (1222), it seems that there were no further conflicts between Nicaea and the Latin Empire.

In 1224 Emperor John III Vatatzes crushed the Latin forces at Poimanenon, and as a direct result of that victory almost all the Latin territories in Asia Minor came under Nicaean control. In the 1230s, Emperor John of Brienne launched the final Latin military operation in Asia Minor, which resulted only in the brief recapture of the coastal town of Pegai. In 1234, John III crossed to Europe and captured Latin territories in Thrace and eastern Macedonia. In 1235-1236 the Nicaean emperor and his ally, the Bulgarian tsar Ivan Asen II, jointly besieged Constantinople by land and sea, but to no avail. The main reasons for this failure lay with Ivan Asen’s change of sides twice during the siege of Constantinople and with the subsequent defeats of the Nicaean fleet in sea battles against the Venetians, who had come to the aid of the Latin Empire in 1236.

Nicaea and Venice had further naval encounters in the 1230s over the lordship of the island of Crete, in which Nicaea failed to achieve long-term results. The significant military aid that reached Constantinople in the late 1230s interrupted the Nicaean advance against the Latin Empire, but only temporarily. Specifically, in 1241, the Thracian town of Tzouroulon came under Latin control when Western military reinforcements arrived in the area, but the city again came under Nicaean authority in 1247.

By the late 1250s, the Nicaean Empire had under its control all the former territories of the Latin Empire, apart from the city of Constantinople itself. In autumn 1259, in the valley of Pelagonia, the Nicaean forces achieved a significant victory against the triple military coalition of the principality of Epiros, the Angevin kingdom of Sicily, and the Frankish principality of Achaia, which threatened Nicaean plans to restore the Byzantine Empire. The liberation of Constantinople by the Nicaeans took place by chance in July 1261: General Alexios Strategopoulos was passing outside Constantinople on his way to the Bulgarian borders with a small number of Nicaean soldiers when he found the city almost unguarded because most of its Latin garrison was absent besieging the castle of Daphnousion on the Black Sea coast.

Encountering no resistance, the Nicaean troops entered Constantinople on 25 July 1261.

Emperor Michael VIII entered the city on 15 August, the day of the Assumption of the Virgin, and in September he was crowned “emperor of the Romans” for the second time (the first was in Nicaea in 1259) in the church of Hagia Sophia, according to Byzantine tradition. The Nicaean emperor had thus restored the Byzantine Empire.

During the Latin occupation of Constantinople, Nicaea attempted to establish diplomatic ties with the Latin Empire and Venice, as well as with the Holy Roman Empire and with Genoa. In 1214, Theodore I Laskaris granted Venice commercial privileges for five years, although these were not renewed. In the late 1210s Theodore I Laskaris married Maria, the sister of the Latin emperor Robert, and proposed the marriage of one of his daughters to Robert himself. Most probably in 1244, John Vatatzes married Constanza, daughter of Frederick II, Holy Roman Emperor and king of Sicily, thus sealing the good relations between Nicaea and the Western Empire, which had included military and financial help from the Nicaean emperor to Frederick II. On 13 March 1261, at Nymphaion, Emperor Michael VIII granted Genoa commercial privileges in exchange for military help against Venice.

The Latin Empire was only one of the enemies that the Empire of Nicaea had to face. The Turks of the Saljûq sultanate of Rûm, with their capital at Ikonion (mod. Konya, Turkey), signed a secret treaty with the Latin Empire (1209) and laid claim to territories of the Empire of Nicaea during the first years of its existence. The Saljûq attacks ceased after the battle at Antioch in Pisidia (mod. Yalvaç, Turkey), near the river Meander, in spring 1211, when the Nicaean forces defeated the Turkish army and killed the sultan. After 1204, another independent Greek state in Asia Minor, the Empire of Trebizond, under the brothers David and Alexios Kom- nenos, attacked the Empire of Nicaea, occasionally with the help of the Latin Empire of Constantinople. In 1214, Theodore I annexed Paphlagonia, the territory of David Komnenos, and extended his dominions to the southern coast of the Black Sea. The rivalry with the principality of Epiros, Nicaea’s main Greek opponent in the contest for the throne of Constantinople, reached its peak in 1222, when the ruler of Epiros proclaimed himself “emperor of the Romans” at Didymoteichon in Thrace, and ended in 1259 with the battle of Pelagonia. Interestingly, the first military engagements with the kingdom of Bulgaria, the only non-Greek contestant for the throne of Constantinople, took place during the reign of Theodore II Laskaris and ended with a peace treaty in 1256, which was sealed later with a match between the two royal families.

Despots and Emperors of Nicaea

Theodore I Laskaris (emperor 1208)


John III Vatatzes


Theodore II Laskaris


John IV Laskaris


Michael VIII Palaiologos


Restoration of Byzantine Empire


under Michael VIII


After 1204, Nicaea was recognized by the papal legates in Constantinople and later by the pope himself as the center of the Greek Orthodox East. In the discussions between Latins and Greeks regarding the ecclesiastical and dogmatic differences between their respective churches that took place shortly after the Latin conquest of Constantinople, the papal legate in Constantinople invited the participation of the Nicaean clergy, but not that of the other Greek states that emerged after 1204. In 1214, ecclesiastical negotiations that had started in Constantinople continued in the Empire of Nicaea, while in 1232-1234 there was an exchange of letters between Pope Gregory IX and Germanos II, the Greek patriarch of Constantinople in exile, leading to formal negotiations between the two sides in the Empire of Nicaea. In the 1240s and 1250s, the negotiations continued, with the encouragement of the Nicaean emperor John III, and in the early 1250s the two sides appeared to be closer to an agreement than ever before regarding the reunification of the two churches, but in the end no agreement was signed, most probably because of disagreement over the lordship of Constantinople, which the Nicaeans demanded in exchange for acknowledgment of papal primacy.

Under John III Vatatzes and Theodore II Laskaris, the economy of the empire flourished, enabling them to engage the services of mercenaries and also to make the empire the cultural center of the exiled Byzantines. After 1204, Niketas Choniates and Nicholas Mesarites lived in the Nicaean Empire, while the teacher of Emperor Theodore II Laskaris, the scholar Nikephoros Blemmydes, wrote and taught there. The flourishing economy allowed the Nicaean emperors to establish hospitals, build churches, and fortify many towns on the borders of the empire. From the reign of John Vatatzes on, the Nicaean economy was much healthier than the Byzantine economy had been under the Angeloi, a prosperity that contributed significantly to the stability of the Byzantine Empire after 1261.

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