The First Military Gate, in Turkish known as İlk Askeri Kapı, is the southernmost gateway of the Theodosian Walls of Constantinople, located at the junction with the Sea Walls that ran along the Sea of Marmara. The gate is situated next to the Tower 1 of the Theodosian Walls, just to the north of that tower. This area is called the Yedikule neighbourhood and several important historical building of different eras can be seen in the vicinity of the gate.

Names and characteristics of the gate

The First Military Gate was restored in the period from 1991 to 1994. It is just 2.3 meters wide and 4.4 meters high. It is actually a small postern, and because of this, in the traditional nomenclature established by Philipp Anton Dethier in 1873, the gate was classified as a military gates. According to this approach, this particular gate was to enable troops fast access to the city, while the civilians were not allowed to use it.

This gate, like other gates of the Theodosian Walls, has several names. The most characteristic one is the Gate of Christ because it features a wreathed Chi-Rhō Christogram on the inner façade of its arch. Christograms are the combinations of letters that form an abbreviation for the name of Jesus Christ, and are traditionally used as a religious symbol within the Christian Church.

Another one of the gate's intriguing names is Tabak Kapı, which means the Gate of the Tannery in Turkish — a nod to the bustling leather trade that once thrived nearby. After Mehmed II conquered Constantinople, tanners were settled in and around Yedikule and Kazlıçeşme, creating a vibrant hub for leather production. By the late 15th century, some 360 tanneries were operating in the area, and by 1638, the trade had grown into a sprawling industry: roughly 5,300 shops and 15,000 workers were involved in leather making and sales.

The famous 17th-century traveller Evliya Çelebi, chronicling the tradesmen of Istanbul, noted the 300 tannery shops in Yedikule, giving a glimpse of the district's busy economy. Even in 1726, the tanners were active in local governance: they petitioned the qadi to remove their guild elder, Imam Musa, for breaking official price rules and causing unrest. They also requested that Hacı Abdullah replace him, showing that the leather workers were not just skilled artisans but also deeply involved in their community's affairs.

First Tower of the Theodosian Walls

The gate stands in the shadow of the Tower 1, the first of 96 towers of the Theodosian Land Walls. Originally erected as the integral part of the Theodosian Walls of Constantinople in the period from 404 to 413, this hexagonal tower was preserved up to the platform level. It was subsequently reconstructed in the same period as the First Military Gate, between 1991 and 1994. It has three floors and was erected from interchanging rows of stones and red bricks.

This tower has a Greek inscription stretching across its façade near the top. The inscription belongs to Eastern Roman emperors Basil II and Constantine VIII from the 11th century. It states that it is the "Tower of Basil and Constantine, faithful Emperors in Christ, pious Kings of the Romans".

Constantine VIII held the title of Byzantine emperor from 962 until his death, but his path to power was anything but straightforward. The younger son of Emperor Romanos II and Empress Theophano, Constantine spent most of his life as a nominal co-emperor, sharing the throne first with his father, then his stepfather Nikephoros II Phokas, his uncle John I Tzimiskes, and finally, his formidable brother Basil II. When Basil — the legendary "Bulgar Slayer" — died childless in 1025, the sixty-five-year-old widower Constantine finally became the sole ruler.

Though he had technically occupied the imperial throne for an astonishing 66 years — making him the longest-reigning Roman emperor on record — Constantine had spent most of that time enjoying the trappings of power rather than wielding it. Even as sole emperor, he showed little interest in governing, preferring comfort and leisure over political reform or military campaigns. His brief solo reign lasted less than three years, closing a chapter on a life defined more by privilege than by action.

Another intriguing relic from Tower 1 is a Greek inscription etched carefully above one of its windows. Unlike ordinary carvings, this one is a Greek tetragram, a sequence of four letters that holds a powerful meaning. Once deciphered, the inscription reveals a striking proclamation: "Jesus Christ conquers."

Marble Tower

The Marble Tower (which translates into Turkish as Mermer Kule) stands proudly where the mighty Theodosian Land Walls meet the Sea Walls of the Marmara (the ancient Propontis), marking the southwestern edge of Byzantine Constantinople. Once the westernmost tower along the Marmara Sea Walls, this impressive structure was not merely a defensive outpost — it formed the heart of a fortified complex, complete with a central courtyard and its own cisterns.

The remains tell a story of grandeur and strategic design. A massive four-story tower dominates the site, accompanied by an eastern bastion slightly to the northeast. Between them stretches a curtain wall with crenelated parapet-walks, narrow loopholes for archers, and two-story casemates, all arranged around a courtyard where cisterns once supplied water to the complex. Together, these elements reveal a structure that served both as a fortress and as a residence.

The Marble Tower complex is a compact yet heavily fortified enclosure, dominated by its main tower, Marble Tower, built largely of marble spolia. A curtain wall connects it to a smaller northeastern tower, creating a defensible space that differs markedly from the Early Byzantine walls. The complex sits between the southernmost tower of the Theodosian Walls (Tower 1) and Tower 102 of the Marmara Sea Walls. Today, only traces of its southern curtain wall survive, and the area has changed dramatically since the mid-20th century. Most of the curtain walls between Marble Tower and Tower 1 were demolished to make way for a highway in the 1950s, and the shoreline was artificially extended by about 20 meters. Originally, the tower was nearly surrounded by water on three sides, enhancing its defensive position.

The main tower rises impressively on a plan of approximately 10 by 10.8 meters, reaching around 25 meters in height. Constructed of large marble blocks up to the level of the curtain walls, it consists of four stories topped with a crenelated parapet. Within the courtyard, four arched openings punctuate the tower — two on the lower floors, one at the parapet level, and a fourth on the uppermost floor. The lower stories are roughly 4 meters thick, with arched niches housing arrow slits that once defended the complex. The tower's inner walls are formed from large limestone blocks, while arches and vaults are constructed in brick. Each floor is crowned with a brick domed ceiling, many featuring cross motifs.

Small windows line the upper floors on three sides, with arched stone plates above the third-floor windows and stone lintels above the fourth. The northeastern tower is more modest, measuring around 6.5 meters across with two vaulted floors. The curtain walls of the complex, roughly 3 meters thick, are built from limestone blocks, likely reused from older structures. Above the upper cornice, the masonry alternates between three layers of small limestone blocks and three layers of brick. Within the courtyard, arches follow a repeating pattern of a single limestone block followed by three bricks. Two levels of casemates are separated by cornices, and each niche features an arrow slit. Another cornice runs between the second level and the battlements.

The exterior walls are marked by two prominent cornices: one at the level of the lower curtain niches and courtyard floor, and another at the battlement level. While many of the curtain wall cornices were replaced during restoration, some original fragments survive. Among these are lotus-palmette friezes, possibly taken from a domed cross-in-square church dating to the 11th or 12th century. Another fragment in the upper niche of the western curtain wall bears a Palaiologan monogram at its centre, flanked by crosses and lattice motifs — potentially a Kantakouzenos monogram.

Within the courtyard lie the remains of four small cisterns. The two principal cisterns, situated along the eastern wall, have rectangular plans with bevelled corners, measuring approximately 5 by 4 meters. Part of the vaulting of the southernmost cistern, about 1.7 meters high, has survived. The waterproof plaster lining the walls is about 3 cm thick. A terracotta pipe connects the second and third cisterns, though the third survives only partially. The fourth cistern is a small round tank positioned near the northeastern tower, completing the complex's sophisticated water system.

Much of the complex was lost during the construction of the modern coastal road, which buried its lower levels beneath today's ground surface. What survives displays remarkable craftsmanship: stone blocks and marble form the lower courses, with alternating rows of stone and brick rising up to the second moulding. The polychrome arches and vivid masonry unmistakably point to the Late Byzantine period. The abundant use of repurposed materials — woven into both the masonry and the decoration — adds yet another layer to the site's centuries-spanning story.

The site has long been debated by scholars seeking to identify its historical phase and patrons. It has been associated with the palace of Theodoros Palaiologos Kantakouzenos (ca. 1402–1410), mentioned in a poem by John Chortasmenos and linked to a cornice inscribed with the monograms of the Palaiologos and possibly Kantakouzenos families. Yet, as the poem locates that palace on a hill, this description conflicts with the seaside position of the Marble Tower.

John Chortasmenos, a scholar and poet of late Byzantium, composed an epigram celebrating the newly built palace of Theodoros Palaiologos Kantakouzenos in Constantinople. The poem was no ordinary dedication—it was crafted in the voice of the palace itself, a structure brought to life through verse, offering praise to its patron and builder.

The poem's reception, however, was not entirely smooth. In a surviving letter, Chortasmenos defends his work before a patriarchal official, Michael Balsamon. He acknowledges that some critics found his verses "uncouth," but insists that Kantakouzenos himself guided the composition, even requesting certain revisions. The exchange reveals not only the delicate relationship between poet and patron in late Byzantine court culture but also the enduring tension between artistic expression and imperial taste.

Another interpretation of the Marble Tower connects it to an earlier stronghold constructed near the Golden Gate, known as the Chryseia Castle (kastélion tēs Chryseías), dated to the mid-14th century. After the civil war of 1354, John VI Kantakouzenos (r. 1347–1354) handed this fortress — newly restored and refortified — to Emperor John V Palaiologos (r. 1341–1391). John V later rebuilt and reinforced it, dismantling nearby churches — the Church of All Saints, the Church of Forty Martyrs, and the Basilica of St. Mokios — to reuse their materials in the new walls.

He resided in this fortified residence in 1390, when his rebellious grandson John VII temporarily seized Constantinople. Soon after, under pressure from the Ottoman sultan Bayezid I (r. 1389–1402), who threatened to blind the emperor's son and heir, the future Manuel II Palaiologos, then an Ottoman hostage, John V was forced to dismantle much of the fortress. Contemporary texts refer to this complex as the Fortress of the Golden Gate or the Polichnion (Little Town) of the Golden Gate.

The spolia — the reused materials visible throughout the Marble Tower's structure — may originate from this very phase of construction. The cornice bearing the Palaiologos and Kantakouzenos monograms, rather than marking original ownership, could instead be reused ornamentation from the dismantled fortress.

Standing close to the Golden Gate and once possessing its own small harbour, the Marble Tower complex demonstrates extensive use of building materials repurposed from dismantled churches. Earlier misreadings of the sources led scholars to search for the site elsewhere, but recent architectural, archaeological, and textual analyses confirm that the Marble Tower complex is best identified with the Polichnion of John V Palaiologos — a Late Byzantine fortified residence that bridged the line between imperial retreat and coastal defence.

Yedikule neighbourhood

Yedikule neighbourhood of the Fatih distinct of Istanbul has been named after the Fortress of Seven Towers located around 500 meters to the north-east of the First Military Gate. A former Greek neighbourhood, Yedikule is located on the shores of the Sea of ​​Marmara, between the Kocamustafapaşa district of Fatih and the Kazlıçeşme district of Zeytinburnu. The Yedikule neighbourhood is home to dozens of historic mosques and fountains, along with city walls, towers, and numerous historic Ottoman houses. Recently, it has received a significant number of immigrants from the Middle East and Africa, particularly since the Syrian Civil War.

Urbanized in the 16th century, the neighbourhood became a hub for industrial and agricultural activities, such as the tanneries already mentioned above. Additionally, Yedikule also became host for some establishments like slaughterhouses, soap and candle makers, and workshops.

Yedikule neighbourhood was also known with its gardens, which were renowned for its cabbages and lettuces and used more than 1500 years. According to the guarantor books of year 1735, there were 344 gardens in the area, including nine gardens in the Surdibi area, which stretches between Yedikule Fortress and Silivri Gate. According to a map from 1835, there were 102 gardens. Yedikule became highly populated after the population boom in Istanbul between 1940s and 1980s. As a result of that, the gardens and industrial areas became residential areas and some parts of the gardens were used for building the streets and creating waste-filling areas in the 1970s.

Remnants of the Byzantine period are also evident in the district's architecture. One of the most significant buildings from the Byzantine era within the Yedikule neighbourhood is the Stoudios Monastery, later transformed into the İmrahor Mosque. It was founded in the mid-5th century by the patrician Stoudios and dedicated to St. John the Baptist. Located near the Golden Gate, it is considered the oldest church in Istanbul. Originally, a grand three-aisled basilica with a porticoed atrium, narthex, and richly decorated nave with green marble columns, it once housed exquisite opus sectile floors and a cruciform crypt, likely containing sacred relics.

The monastery gained fame under Theodore of Stoudios (759–826) during the Iconoclast period as a bastion of image veneration. It became a self-sufficient, thriving community, with gardens, vineyards, mills, livestock, workshops, and even a wharf. Beyond its economic and spiritual role, Stoudios emerged as a centre of intellectual life, fostering hymnography and manuscript production, including the renowned Theodore Psalter. Its rules influenced many later monasteries, including those on Mount Athos.

Politically, the monastery maintained independence, sometimes acting as a place of confinement for deposed emperors such as Michael V and Isaac I Komnenos. Though it declined during the Latin occupation, it was restored in 1293 and remained a leading monastery until its conversion into a mosque by İlyas Bey, stable master to Bayezid II. Damaged by the 1894 earthquake, the site was partially excavated in the early 20th century, revealing its opus sectile floors, crypt, and burials. In 2012, the monument came under control of the General Directorate of Foundations and the restoration project was prepared. As of 2025, the works were still ongoing.

The most famous historical Ottoman monument of the neighbourhood is Hacı Evhadüddin Mosque. The mosque is a modest yet fascinating 16th-century mosque, originally built in 1585 by Mimar Sinan as part of a small complex with a tekke and fountains. Its founder is remembered as Kasap Hacı Evhadüddin, "the generous butcher," whose piety is immortalized in a poetic inscription once displayed above the gate.

The mosque's courtyard holds Hacı Evhadüddin's simple tomb, and over the centuries the building received care and restoration. In 1850–51, Sultan Abdülmecid I repaired the mosque at the request of a Naqshbandi sheikh, adding a new fountain and leaving his imperial monogram and a dedicatory inscription. After the 1894 earthquake, further repairs were made. By the early 20th century, however, the mosque had fallen into ruin, scarred by neglect and possibly by fire. Photographs from the 1930s and reports from scholars like Semavi Eyice describe it as little more than a derelict shell. Salvation came in 1945, when the Gezer family sponsored a full restoration, rebuilding its prayer hall, wooden minber, and galleries.

Architecturally, Hacı Evhadüddin Mosque belongs to the group of Sinan's small, rectangular neighbourhood mosques, akin to the Ramazan Efendi and Ferruh Kethüda mosques. It once boasted beautiful Iznik tiles, traces of which could still be seen in the 1940s, though none survive today. The associated tekke has long since vanished, and while a nearby hammam was traditionally linked to the mosque, it is stylistically later and not by Sinan. As one of Sinan’s final works — completed only a few years before his death in 1588 — the Hacı Evhadüddin Mosque stands as a quiet reminder of Istanbul's layered history: a simple neighbourhood mosque shaped by imperial patronage, local devotion, and centuries of decline and renewal.

Until recently, the district housed a significant non-Muslim population, including Greek and Armenian churches and minority schools. The Yedikule Holy Saviour Armenian Hospital, known in Armenian as Surp Pıgiç Hastanesi, is one of Istanbul's most important historical healthcare institutions. Founded in 1832 by decree of Sultan Mahmud II, it was established to serve the city's growing Armenian community, though its doors have always been open to people of all backgrounds.

At the heart of the hospital complex stands the elegant Chapel of the Holy Saviour, completed in 1834. Designed by the Armenian architect Hovhannes Amira Serveryan together with the imperial architect Garabed Amira Balyan, the chapel reflected the refined architectural style of 19th-century Istanbul. Over time, it fell into disrepair but was beautifully restored in 1906 by Krikor Melidosyan and Yeğiazar Avedisyan, regaining its place as a spiritual and cultural landmark for the city's Armenians.

The hospital not only functioned as a medical centre but also became a focal point of philanthropy, education, and cultural life, closely tied to the Armenian community's charitable foundations. Its survival through the upheavals of the late Ottoman and Republican periods is a testament to its resilience and enduring service. Today, nearly two centuries after its founding, Yedikule Surp Pıgiç Hospital continues to operate, carrying forward its legacy as both a healthcare institution and a historic symbol of Istanbul's multicultural past.

The Yedikule Gasworks (Yedikule Gazhanesi), established in 1880, marked a pivotal moment in Istanbul's modernization. As the city's first public gas facility, it was designed to illuminate the streets of the historic peninsula, transforming Istanbul's nightlife and urban landscape. Initially, the gas produced powered 400 street lamps, and over time, the network expanded to include neighbourhoods like Eyüp, Bakırköy, and Yeşilköy. The gasworks operated under various entities, including the Ottoman Lighting Company and the Üsküdar-Kadıköy Gas Company, before being managed by the Istanbul Electricity, Tram, and Tunnel Company (IETT) until its closure in 1993.

Following its decommissioning, the site fell into disrepair, becoming a neglected industrial relic. However, recent restoration efforts have breathed new life into the complex. The Yedikule Gasworks is now being transformed into a vibrant cultural hub, blending its industrial heritage with contemporary innovation. The redevelopment project aims to celebrate the site's historical significance while fostering a space for modern creativity and community engagement.