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Niketiaton Fortress
Niketiaton Castle (Eskihisar).jpg

The Castle of Niketiaton (Νικητιάτων) is located by the shore near the entrance to the Gulf of Nicomedia 42 km west of Nicomedia (modern İzmit). Now known as Eskihisar (“Old Fortress”), it is around 3 km south of Dakibyza (modern Gebze). Niketiaton was also the site of a monastery and settlement.

The Niketiaton Castle was part of a series of fortifications protecting the main highway leading to the eastern frontier. They also protected ports linked to the south shore, thus the food supply to the capital traveled over these waters. This area of Bithynia (Mesothynia, the peninsula of Nicomedia) retained its strategic military important throughout the entire Byzantine period.

In the Early Byzantine era, the port at Eskihisar was known as the port of Dakibyza. Niketiaton was the name of a monastery founded in the ninth century by the magister Sergius, who came from Niketia  (near Amastris) in Paphlagonia. It was on the gulf of Nicomedia between the emporia of Kalos Agros and Dorkon, neither of which has been precisely located. The name reappears in 1241, when the castle of Niketiaton was taken by John III Vatatzes in his campaign against the Latins.

After recapturing Constantinople, Michael VIII Palaiologos blinded the young legitimate emperor John IV Laskaris on Christmas day 1261. John was then confined to Niketiaton, where he was under guard, but guaranteed a supply of food. Michael VIII was excommunicated a few months later by the patriarch Arsenius, but this was lifted by a new patriarch in 1267. In turn, Michael showed him good will, ordered food, clothing, and provisions sent to the prince, though never released him. John was still at Niketiaton when Michael’s son Andronikos II came to visit him to seek his recognition. In 1314, a priest of the castle of Niketiaton was defrocked for spreading slanderous propaganda against the emperor.

It is mentioned in the account of the Battle of Pelekanon (1329) as one of the fortresses Byzantine soldiers fled to after Andronikos III was wounded. It became Ottoman after the fall of Nicomedia in 1337, though it was briefly retaken by the Byzantines in the aftermath of the Timur’s defeat of the Ottomans in 1402. In 1399, the castle was unsuccessfully attacked by the French Marshal de Boucicault when he commanded forces to relieve Constantinople when it was being besieged by the Ottoman Sultan Bayezid I. It was recaptured by the Ottomans in 1421.


The entire fortress measures about 120 x 80 m., and consists of two main parts: the original inner fortress and an outer circuit of wall. There was also an outer wall and ditch along the north face. It seems there are three construction phases; the inner fortress dates to the Komnenian era (probably to the reign of Manuel I), while the outer walls date to both the Laskarid and Palaiologian eras.

The inner castle, in the northwest corner towering above the rest of the fortifications, is a massively fortified but well-lighted rectangular residential hall of four stories. This tower-house was evidently the site where John IV Laskaris was confined. It is rectangular in plan (30 × 62 m) with a courtyard protected by four square towers. There are two large projecting square towers on its north face, where the castle was most vulnerable, and less impressive towers on the corners of the south wall. The interior palace-like structure, which measures 15.2 x 10 m internally, contained a basement (cistern), three residential floors and a rooftop platform. Each of the four floors consisted of a large hall. The outer north wall that faced the enemy is around 3 m thick and has no windows. The west and south walls had arched windows on the two upper stories, which overlooked the castle and offered panoramic views across the gulf. The main entrance to the palace at the southeast corner appears to have been a simple arched opening. It has layered masonry of single bricks and ashlars, including cloisonné and brick ornaments.

The second circuit represents an expansion of the original castle by adding a large wall on the west and south of the inner fortress. It had seven towers. Four large semicircular towers occupy the corners and protect a gate in the north wall. The south wall, overlooking the gulf, was reinforced by two solid square towers and four small square bastions. The walls are homogeneous in structure and masonry, evidently the product of one period.

Palace of the Porphyrogenitus (Tekfur Sa
Nymphaion Palace.jpg

Constantinopolitan Palace of the Porphyrogenitus and Laskarid Palace in Nymphaeum 

The palace-like structure of Niketiaton Castle is strikingly different from the ancient palace tradition of large urban complexes with peristyle courtyards. Instead this style of palace is centered on a single block-shaped unit that is several stories high with an exterior façade. It can be compared with the so-called Palace of the Porphyrogenitus (Tekfur Sarayı) in Constantinople and the Laskarid palace at Nymphaeum. As its defensive qualities of these palaces seem exaggerated, it might be following the model of the tower house, which had become a common aristocratic residence following the collapse of the Byzantine frontier in Anatolia. The defensive features, then, would have likely emphasized the prestige of landownership and power of its residents. Its layout has also been compared to Italian palaces from this period, as can be seen in the Genoese Palazzo Comunale in Galata, which was rebuilt in 1315. Other possible influences could have come from the East, in Arabic, Armenian and Seljuk palaces.

Eskihisar Marina (location of Niketiaton harbor?)

While the town of Tzouroulos was being besieged by the Italians, the emperor John prepared several triremes and, taking with him not a small army, made an attack on the Italians. Setting off from Nikomedeia, and passing by Charax, he besieged Dakibyza on the spur of the moment and took it, and the fortress of Niketiatou besides, and made this also subject to him. However, at that time he was unlucky with his triremes since the men on board were inexperienced in fighting and Iophre the Armenian, who had the rank of commander among them, was rather hesitant in matters of war. Before him Manuel Kontophre had been granted the command of the triremes, a man who was brave in arm and had a warlike spirit on land and on sea. But some days earlier he had addressed bold statements to the emperor about the navy; for he had said that our triremes would not match those of the Italians even if they were to be multiplied in number in relation to them—for he knew precisely the circumstances of both—and so he was dismissed from the command and Iophre succeeded to it and suffered a very serious defeat. For he had command of 30 triremes but was defeated by 13, losing as many ships as the enemy had; each one of the enemy ships gained one trireme as spoil, with its men and weapons.

From The History by George Akropolites

Photo by Paul Vuccino (1870)

SALT Research

For all that, there reached to the Sublime hearing that in Constantinople’s vicinity some settlements, places, and villages (which had been conquered by the [sultan’s] ancestors and the forefathers, who now reside in Paradise, and the troops of the Jihad bivouac; in particular, the king and the heavenly resident Orhan-Khan) were joined again to “the Land of War” by the kings of infidels, because of the anarchy that occurred during Emir Timur[’s times] and the damage from the contest between the sultan’s brothers for the Caesar’s Throne. Over the course of time, the lord of Istanbul and others seized those places. “Once again equipping troops of mujāhids, we shall entrust to them the conquest of that country and we wish all the land to be conquered and to be turned into waqf becoming good land” – with these righteous intentions [the sultan] sent to conquer it Temirtaş’s son Umur-bek, along with the army of valiant mujāhids. According to the promise “Whoever is God’s God is his,” which pleases the heart, when the army of Islam moved in that direction, at the very beginning, in the vicinity of the city of Iznikmid, which was in the sultan’s possession, the guardians of the fortress of Hereke, who had resigned themselves to Istanbul in the time of the emir Timur’s anarchy, left the fortress empty and fled to Istanbul. As soon as that spacious region came into the possession of the Islamic people without struggle and hostilities, [the sultan’s troops] went out of it and advanced to the town of Guyebize, located one day’s journey from Istanbul. The infidels of that place, setting hopes on the strength of [their] fortifications, had in mind war and rebellion and were prepared for opposition and defense. Willingly or not, the mujāhid soldiers, the brave spirits and heroes of battlefields, with effort, endeavor, and exertion, mercilessly attacked the fortress, and conquered the fortress of Guyebize with ease. The army of Islam seized uncountable spoils, put in order the city and its vicinities by the laws of the faith and the rules of the true justice, appointed ḥākim and qāḍī, and assigned [all] necessary for governing the country. From there [the army] approached the place of Nekite and the fortresses of Pendikla and Kartal. From fear of the mujāhids’ punishment all of them hastened to obey, and the fortresses’ guardians left fortifications and castles and fled to Istanbul, while Umur-bek sent courageous men and, taking hold of all the castles, joined [them] to “the Land of Islam.” When all those settlements and fortresses – with their surrouding regions, arable lands, and pastures on the sea coast from the city of Iznikmid to the coast of the passage to Istanbul – were conquered, the sultan, owner of the Muḥammadan qualities, in accordance with what he had in his sublime mind, turned into waqf all those settlements and places as his gift to God and also increased those waqfs by adding other profitable grants and highly gainful lands. Up to now, those excellent madrasas have been extremely populous, and the best of all the madrasas of the city of Bursa and their professors’ and students’ allowance has been more abundant and more significant than in all other madrasas of the sultans of Rūm: for instance, their professors’ everyday allowance, with other incomes, exceeds 100 akce. Imarets, zaviye, darulziyafe, inns, places of eating and meeting are uncountable and so numerous that the magnificence of the Sultans of the Universe becomes exceptional.

Conquest of Niketiaton and the region by Mehmed I from Hasht Bihist by Idris Bitlisi

Plan by Foss



Belke, K. Bithynien und Hellespont (Tabula Imperii Byzantini 13)

Foss, C. Survey of Medieval Castles of Anatolia II: Nicomedia

Janin, R. Les Eglises Et Les Monasteres Des Grands Centres Byzantins: Bithynie, Hellespont, Latros, Galèsios, Trébizonde, Athènes, Thessalonique

Shukurov, R. The Byzantine Turks, 1204-1461

Yücel, E. & Soyhan, C. Gebze ve Eskihisar

Avcı, H. & Özbay, I. “Eskihisar Kalesi 1994 Yılı Kazı Çalışmaları” (MKKS 6)

Dirimtekin, F. “Pelekanon, Philokrini, Nikitiaton, Ritzion, Dakibyza” (Fatih ve İstanbul, İstanbul Fethi Derneği, Cilt 2)

Niewöhner , P. “The late Late Antique origins of Byzantine palace architecture”

Primary Sources

Hasht Bihist by Idris Bitlisi (from Shukurov, R. The Byzantine Turks)

The History of Georgios Pachymeres (Books I and II translated by Nathan John Cassidy)


Niketiaton Castle Album (Byzantine Legacy Flickr)

Byzantine Bithynia Album (Byzantine Legacy Flickr)

Eskihisar Kalesi (Kültür Portalı)

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