During the Yenikapı excavations conducted in the Fatih district of Istanbul, shipwreck remains shedding light on the city’s maritime history were uncovered. A total of 36 shipwrecks, dated between the 5th and 10th centuries, provide valuable information about ship types and naval technology of the Byzantine Period, while also offering significant insights into the commercial activities of the era. Maritime equipment, anchors, ropes, and various materials unearthed during the excavations vividly reveal the maritime practices and understanding of the time. The Yenikapı shipwrecks are among the important archaeological findings contributing to the interpretation of Istanbul’s historical fabric.

^{The Yenikapı Shipwreck Excavation Site - (Governorate of Istanbul)}

The Excavation Process and Historical Background

The Yenikapı Rescue Excavations were initiated in 2004 under the direction of the Istanbul Archaeological Museums as part of the Marmaray and Metro projects, which aimed to improve Istanbul’s transportation infrastructure. These operations included extensive archaeological investigations that led to the unearthing of the ancient Theodosius Harbor. Re-established as the capital by the Roman Empire in the 4th century, Istanbul served as the capital city of three major empires throughout history and remains one of Turkey’s largest and most cosmopolitan cities today. Before the construction of the Marmaray Railway and Metro lines, archaeological rescue excavations were carried out around the stations of Üsküdar, Sirkeci, Sultanahmet, and Yenikapı. Notably, the discovery of the Byzantine-period Theodosius Harbor at Yenikapı stands as one of the most significant outcomes of these excavations.

Excavation Site and Findings

The excavations were conducted over a total area of 58,000 square meters, within a fill layer approximately 12 meters thick. As a result of these investigations, it was revealed that the region contained multiple cultural strata ranging from the prehistoric Neolithic Period to the Ottoman Era. It was determined that Theodosius Harbor had been established within a natural bay, gradually filled in over time by alluvial deposits carried by the Lykos (Bayrampaşa) Stream, leaving the present-day shoreline approximately 300 meters inland.

Scientific Collaborations

The excavations were carried out under the leadership of the Istanbul Archaeological Museums Directorate, with the participation of both domestic and international universities and research institutions. Scientific support was provided from a range of disciplines, including ship archaeology, conservation, osteoarchaeology, archaeobotany, geology, philology, dendrochronology, prehistory, and anthropology.

Prominent Discoveries

The excavations yielded hundreds of thousands of organic and inorganic artifacts, along with architectural remains. Notably, 36 shipwrecks dating from the 5th to 10th centuries were uncovered, representing the world’s largest and best-preserved assemblage of shipwrecks from the Early and Middle Byzantine Periods. Among these, the discovery of galea-type galleys constitutes the first known archaeological examples of oared warships used by the Byzantine navy.

^{Archaeological Finds Unearthed During the Excavations - (Anadolu Agency)}

Theodosius Harbor

Theodosius Harbor was constructed by the Byzantine Emperor Theodosius I (379–395) along the coast of the Sea of Marmara, in the twelfth region of Constantinople. As the city’s second-largest commercial harbor of its time, it was established in a deep bay where the Lykos Stream (modern Bayrampaşa Creek) flowed into the Marmara Sea, due to the inadequacy of the existing harbors. A breakwater extending from west to east was built on the southern side of the harbor, and on its eastern side, in the ninth region, large grain depots such as the Horrea Alexandrina (Alexandrian Grain Warehouse) and Horrea Theodosiana were located. This commercial center maintained its significance until Egypt was conquered by the Arabs in 641.

Function and Operation

Grain and construction materials arriving from ports, especially from Alexandria, were transported into the city through this harbor. Due to the navigational challenges faced by large-tonnage ships while passing through the Dardanelles, interim depots were established on Bozcaada (Tenedos) during the reign of Justinian, and shipments continued from there via small vessels. Following the cessation of grain shipments from Egypt in the 7th century, the harbor gradually lost its former importance, though it remained in use by small cargo and fishing boats between the 7th and 11th centuries. After the 12th century, due to silting by the Lykos Stream, the harbor was completely rendered inoperable and eventually transformed into a landfill area.

Current Condition

Today, the remains of Theodosius Harbor are situated in the area historically known as Langa, between Mustafa Kemal and Namık Kemal streets, which descend from Aksaray to the Marmara shoreline. The region underwent significant urban transformations during the Byzantine and Ottoman periods, and from the 13th century onward, it became notable for its Jewish settlements.

Archaeological Finds

During the Yenikapı Excavations, artifacts from the Neolithic and Iron Ages — including pottery, stone, and wooden tools — were uncovered, along with ceramic vessels from the Classical Period. Coins, glass objects, amphorae, leather sandals, ivory artifacts from the Roman and Byzantine Periods, and Ottoman tiles were also found. Thanks to their stratigraphic contexts, these artifacts have documented the daily life, economic relations, and technological understanding of their respective eras.

Maritime and Trade-Related Discoveries

Among the finds were maritime artifacts such as terracotta plaques bearing the names of shipowners, stone and iron anchors, pulleys, ropes, and amphorae. Of particular note is a depiction of a ship engraved on an amphora dating to the 10th century. Additionally, amphorae from Samos (5th–3rd centuries BCE), Thasos (4th century BCE), and Chios, discovered west of the harbor, stand as important evidence of the ancient trade networks connected to the port.

^{A Shipwreck Unearthed During the Excavations - (Governorate of Istanbul)}

^{Material Cargoes Discovered Aboard the Shipwreck - (Governorate of Istanbul)}

Archaeozoology

Animal remains unearthed during the excavations have provided significant insights into the fauna of ancient Constantinople and its livestock economy. In particular, excavations conducted in Area 100 (2nd Zone) and the 3rd Zone have revealed architectural remains documenting the harbor settlement history of the Byzantine and Ottoman periods. These findings include mortar-bound walls, breakwater stones, pier piles, vaulted structures, and remnants of a Byzantine church.

Architectural Remains

The Yenikapı Excavations are archaeological works conducted within the scope of Istanbul’s Marmaray and Metro Projects since 2004. As a result of these studies, especially the architectural remains uncovered in Area 100 (2nd Zone) and the 3rd Zone, have provided crucial data on the urban and harbor settlement history during the Byzantine and Ottoman periods.

Area 100 (2nd Zone) Excavations

In this area, architectural remains belonging to different periods ranging from the 4th to the 13th centuries AD have been revealed. The principal findings include:

• A wall measuring 51 meters in length and 4.20 meters in width, constructed from cut stones bound with a waterproof mortar (horasan).
• A vaulted structure with an exposed section of 11 meters in length.
• Breakwater and quay stones belonging to the ancient harbor.
• Wooden piles, extending for 43 meters in two rows, are identified as part of a pier structure.
• A hypogeum (underground tomb chamber) dated to the 11th century.
• Remains of city walls from the reign of Emperor Theodosius II (5th century AD).

These findings have confirmed that Area 100 was located in the landward section of the ancient harbor, very close to the shoreline. The site has been declared a “protected archaeological park area” by the regional conservation board, and while protective project works continue, the area remains temporarily closed to visitors.

3rd Zone Excavations

Key findings from the 3rd Zone excavations include:

• More than 25 wooden piers remain.
• Two stone piers dated to the 8th century AD.
• In the upper layers, a three-aisled Byzantine church dated to the 12th-13th centuries, constructed as the harbor was gradually reclaimed.
• 23 original graves are situated around the church.

Conservation and Restoration

The Yenikapı Shipwrecks, which were exceptionally well preserved within the Lykos Creek sediments, consist of Medieval and Byzantine-era ship remains. However, the wooden materials, which remained waterlogged for centuries, face the risk of biological deterioration once exposed to air and cannot be exhibited directly. Conservation processes are therefore initiated concurrently with the excavation.

At the excavation sites, the humidity level of the shipwreck environment is maintained at nearly 100% to prevent drying. After excavation, the wrecks are transferred to conservation pools for desalination. Iron compounds on the wood are cleaned through various chemical methods. Subsequently, techniques such as polyethylene glycol (PEG) impregnation, freeze-drying, and special resin applications are employed to stabilize the wood. After this long-term conservation process is completed, the wrecks are made ready for museum exhibition.

In 2008, the Department of Underwater Cultural Heritage Conservation was established at Istanbul University for the preservation of the Yenikapı Shipwrecks. A Ship Conservation and Reconstruction Laboratory was also put into service within the same scope. Upon completion of the conservation process, it is planned to exhibit 10-15 selected shipwrecks.

The Replica of Yenikapı 12 and Its Launch

Yenikapı 12 is a 9th-century AD medieval merchant shipwreck. It was discovered during the archaeological salvage excavations at Theodosius Harbor and is considered one of the best-preserved examples among the 37 shipwrecks unearthed.

The remains of the church were documented by decision of the relevant conservation board and have been relocated for future reconstruction.

^{Yenikapı 12 Replica - (Anadolu Agency)}

The replica of the shipwreck was constructed faithfully, adhering to the original findings and construction techniques. As part of the European Union-supported project “LIMEN: Cultural Ports from the Aegean to the Black Sea,” carried out in partnership with Istanbul University, the replica was unveiled on October 5, 2017, at RMK Marine Shipyard. After approximately ten years of research, the original construction methods, types of wood, and engineering calculations of the vessel were determined, completing the reconstruction process. The Yenikapı 12 replica holds the distinction of being the first full-scale historical ship model launched into the sea, concretizing Istanbul’s maritime history.

^{The Yenikapı 12 Replica on the Sea - (Istanbul University)}

Exhibition and Museology

Architectural remains, movable cultural artifacts, and shipwrecks uncovered in the Yenikapı, Marmaray, Metro, and Sultanahmet excavations have been presented through various exhibitions on both national and international platforms. Major exhibitions include:

• “Stories from the Hidden Harbor: The Shipwrecks of Yenikapı” (2013): Displayed the cargoes, construction techniques, and personal belongings of captains from ships dating between the 5th and 10th centuries AD, found in the Yenikapı excavations.
• “Medieval Ports from the Aegean to the Black Sea” Photography Exhibition (2013): Organized in Istanbul under the OLKAS Project, this exhibition promoted 45 medieval ports in the region within the framework of maritime trade and cultural tourism.
• “8000 Years of Istanbul in Daylight” (2013): Showcased 8,000 years of cultural artifacts from the Marmaray, Metro, and Sultanahmet excavations alongside works from Byzantine, Roman, Ottoman, and Republican periods.
• “Byzantium: Splendor and Daily Life” (2010, Bonn): Featured over 600 artifacts from the Yenikapı shipwrecks, including a full-scale replica of the Yenikapı 12 shipwreck.
• “From Byzantium to Istanbul: The Port of Two Continents” (2009–2010, Paris): Held at the Grand Palais, this exhibition introduced the Yenikapı Theodosius Harbor excavations and Neolithic human settlements to a wide international audience for the first time.