The Golden Gate (Latin Porta Aurea, Greek Χρυσεία Πύλη) was a monumental triumphal gate of Constantinople. Situated at the southern end of the Theodosian Walls, it marked the beginning of Constantinople’s main street, the Mese, and the end of the Via Egnatia. It originally had bronze statues of Emperor Theodosius and an elephant quadriga as well as gilded bronze doors after which the gate was named. In the mid-15th century, the Golden Gate was incorporated into the Ottoman fortress of Yedikule (“Seven Towers”).

The Golden Gate was remarkably both for its architectural splendor and its military strength. It consists of a triumphal triple archway flanked by square towers. It is built of Proconnesian marble blocks facing a core of limestone blocks, which is markedly different from the alternating bands of brick and limestone of the Theodosian Walls. The entire structure - the marble gate and its two towers - is 66 meters wide.  The central arch of the gateway is higher and wider than the two on each side, a feature it shares with the triumphal arches of Septimius Severus and of Constantine in Rome. It is possible that the tower once had lavishly decorated cornices, possibly with eagles at the corners as seen on the southwestern corner of the northern tower. The gateways have marble doorframes, with monolithic door jambs, molded bases and architraves, and Corinthian pilaster capitals dating to the early 5th century. On the southern door jamb of the original central arch survives, while the original northern doorframe now sits in the central arch, as it was moved there later when the openings were reduced in size and number. A Latin inscription was on each face of the central arch, and while the gilded bronze letters no longer exist, the inscription is known from literary sources. Certain features of the gate were lost around the end of the 19th century, as a christogram on the molding above the central arch was still visible in the late 19th century. In addition, an earthquake in 1894 damaged the tops of the gate.

The gate is actually a double gateway, as there is another smaller gate piercing an outer wall which was presumably built during the Theodosian era. The moat that ran much of the length of the Theodosian Walls was in front of the second gateway. The gate had reused columns and Corinthian capitals supporting an arch, while the outer wall was decorated with mythological reliefs that survived until the 17th century. On each side of the gate were two tiers of marble frames, which enclosed large reused reliefs (almost 2 meters tall) that included sleeping Endymion, Hercules leading Cerberus, Pegasus tended by nymphs, and drunken Hercules. This collection of reliefs was perhaps created in the Middle Byzantine era. In the 1620s there was a failed attempt to acquire the reliefs for the private collections of antiquities of two English noblemen. In 1927, fragments of antique and late antique reliefs (now in the Istanbul Archaeological Museums) were discovered from the outer wall.

There is a debate on whether the Golden Gate, along with its Latin inscription and statuary, dates to the reign of Theodosius I (379-95) or his grandson Theodosius II (402-50). The inscription on the gate references a victory over a ‘tyrant’ (usurper), but the usurper is not named - as was the typical Roman practice. The reference to Theodosius is also unclear, as both emperors named Theodosius defeated usurpers, with Theodosius I defeating Magnus Maximus in 388, while a former primicerius named loannes was defeated at Ravenna in 425 during of Theodosius II.  Historical records also attribute a statue of Theodosius over the gate to both emperors. 

Though the statue and the gate is been attributed to Theodosius II, it has also been argued that the Golden Gate was originally built as a freestanding triumphal arch to celebrate Theodosius I's defeat of Magnus Maximus in 388. One reason for this attributing involves the gate not being an integral part of the land walls, with evidence suggesting the Golden Gate is older than the adjacent walls. If this is the case, it is then possible that Theodosius I already made plans to include this triumphal arch as a gate for the expansion of the city’s land walls, which the praetorian prefect Anthemius would later execute by 413. Furthermore Theodosius I celebrated a victory with a triumphal entry into Constantinople in 391, while there is no record of Theodosius II having a triumph. There are problems with attributing the gate to Theodosius. Firstly, the Golden Gate does not look like any other surviving Roman triumphal arch – only its triple gateway shares any feature with known triumphal arches. Furthermore, the pilaster capitals of gateways arches more likely date to the early 5th century during the reign of Theodosius II. It is plausible, though, that Theodosius I had the arch built and Theodosius II made later additions, including the pilaster capitals and perhaps even its statuary. It has even been suggested that the Golden Gate postdates the Theodosian walls.

The Golden Gate was originally located around 1.5 kilometers away from the Constantinian Wall, where there seems to have been an older triumphal gate. Another gate on the Constantinian Wall, which was built prior to the construction of the Theodosian Golden Gate, was also called the Golden Gate (and also the Gate of Attalus). It is possible it was first called this during the Theodosian era. The Constantinian Golden Gate was extensively decorated with statues, supposedly including one of Constantine that fell down in 740. Even after the walls collapsed in 867, this gate seems to have retained its status as a triumphal gate. The gate itself stood until 1509, when it was toppled by earthquake. It was then known as the gate of Jesus (İsakapı) after an icon of the Crucifixion that was painted on it, perhaps in the Late Byzantine era. The location of this gate is believed to be marked by İsa Kapı Mosque, a small church converted into a mosque.

Just as many other features of Constantine’s new capital, the Golden Gate had a precedent in Rome. The Golden Gate shared many features with the Porta Triumphalis, the triumphal gate of Rome that was apparently only used on special occasions including triumphs. The Golden Gate was on the triumphal route that began at the Hebdomon and continued along the Mese, Constantinople’s main street that was lined with forums and monumental columns. The Hebdomon, located at the seventh milestone, was the equivalent of the Campus Martius, where triumphs traditionally started in Rome. While it is likely that the early Constantinian Golden Gate had influence on the routes of triumphs in Constantinople, the triumphal route was probably firmly established during the Theodosian era when the fora of Theodoisus and Arcadius, with their monumental columns, triumphal arches and statues were built. Other cities, including Antioch and Thessaloniki, had gates with the name Golden Gate, while a Golden Gate was erected in Kiev in the 11th century.

John V Palaiologos (1341-1391) built a fortress known as Kastellion tes Chryseias at the Golden Gate following a bitter civil war in the preceding years. While he resided there by 1390, it was dismantled under pressure from Sultan Bayezid I (1389-1402) in 1391. The fortress was built using material from three churches: the Church of All Saints, Church of Forty Martyrs, and what remained of the Basilica of St. Mokios) he demolished as he could not easily procure building materials. Mehmet II later built the fortress of Yedikule here, replicating what John V had done a century earlier.

Regardless of its dating, it is clear that the Golden Gate was associated with imperial victory from its foundation. Triumphs continued to be celebrated in Constantinople on a relatively regular basis until the 12th century. It also acted as a ceremonial gate for emperors coming from Thrace to enter the city, though they could also enter by sea at the Strategion or even the Great Palace. It is difficult to determine how often the Golden Gate was used in triumphal processions, though there is evidence of multiple emperors making a triumphal entry to the city. Heraclius, for example, entered the city through the Golden Gate in 630 to celebrate his victory over the Persians. Other emperors whose triumphs passed through the Golden Gate include Constantine V, Theophilus, Basil I, John I Tzimiskes, and Basil II. Emperors also entered the city upon being elevated to the throne, as in the case of Nicephorus II in 963. Official visitors of the emperor, such as the legates of several popes, were also welcomed at the Golden Gate. On the other hand, the victorious general Belisarius was not allowed to triumph through this gate, but rather celebrated his triumph in the Hippodrome. By the 11th century it began to be replaced by other routes. Alexios and Manuel Komnenos celebrated their victories, but they did not use the Golden Gate or the Mese for a triumphal procession.  The last known triumphal entry at the Golden Gate was celebrated by Michael Palaiologos when he reconquered Constantinople in 1261. This triumph, held on the Feast of the Dormition of the Virgin, was led by the Icon of the Virgin Hodegetria, with Michael walking behind in solemn procession to Hagia Sophia, where the Patriarch Arsenios performed a second coronation ceremony.

John VI Kantakouzenos (1347-1354), at the end of the Civil War of 1341-47, entered Constantinople by breaching the Golden Gate, which had been walled up, and proceeded to force Empress Anna of Savoy, regent of John V (1341-1391), out of power. In 1354, at the end of another civil war, Kantakouzenos handed over the fortress at the Golden Gate to John V, which he had recently renovated and refortified. It is also recorded that John V built a fortress at the Golden Gate, dismantling the Church of All Saints and Church of Forty Martyrs, as well as the ruins of the Basilica of St. Mokios, to use building material. John V resided in this fortress at the Golden Gate, the Kastellion of Chryseias, in 1390, when his grandson, John VII took control of Constantinople. Sultan Bayezid I (1389-1402) ordered John V to dismantle it in 1391, threatening to blind his son and future emperor Manuel, who was held as an Ottoman hostage at the time. Mehmet II later built the fortress of Yedikule around the same site as the fortress that had been here a century earlier..

The Golden Gate, though, did not its association with victory even as the Byzantine Empire shrank. It was reimagined as a talisman of victory, as legends around it grew, as seen in a legend of Basil I entering the city through the gate, eventually leading to him becoming the emperor. It was also seen as a threat to ruling emperors, as Isaac II Angelos (1185-95) apparently walled off the Golden Gate in fear of prophecies and the talismanic power of antiquities. Even after the Fourth Crusade, its original significance was not forgotten by Michael Palaiologos, though he held the triumph of 1261 in honor of the protectress of Constantinople, the Virgin Mary. The Icon of the Virgin Hodegetria was held aloft by the clergy, proceeding through the Golden Gate and down the Mese, as Michael and his family walked humbly behind. The idea that the Golden Gate had talismanic power continued during the Ottoman era as legends grew around it. There was a belief that Constantine XI Palaiologos, the last Christian emperor of the city, had been turned into a marble and was placed in an underground chamber near the Golden Gate where he would one day awake and restore the empire. It is even possible Mehmet II saw as a potentially dangerous talisman, as he walked off the gate.