Rumeli Hisarı, also known as Yenicehisar, Boğazkesen Hisarı, Yenikale, Başkesen Hisarı and Kara Kale, is a unique witness of Ottoman military construction. This stronghold, located in Istanbul’s Sarıyer district on the European side of the Bosphorus, plays a vital role in the city’s historical environment. Its name refers not only to its architectural splendor, but also to the district that shares its identity. Before the conquest of Istanbul, Fatih Sultan Mehmet built Rumeli Hisarı to control and defend the narrowest point of the Bosphorus, which is only 698 meters wide and right across from Anadolu Hisarı on the Anatolian side. The fortress’s principal mission was to resist naval attacks from the Black Sea, a strategic undertaking that would be critical in assuring the final conquest of the Byzantine capital in 1453.

Architectural Marvel of the Fortress

The style and magnitude of Rumeli Hisarı are quite stunning. The castle is 32,000 square meters and features a series of thirteen bastions connected by sturdy walls. The three tallest towers in the structure are named after the pashas who oversaw its construction: Saruca Pasha, Zağanos Pasha, and Halil Pasha. Saruca Pasha and Halil Pasha skyscrapers reach 28 meters and nine stories, respectively, while Zağanos Pasha Tower rises 21 meters and has eight floors. The tower diameters differ, with Saruca Pasha Tower being 23.3 meters, Zağanos Pasha Tower measuring 26.7 meters, and Halil Pasha Tower measuring 23.3 meters. Wall thickness varies, with the thickest walls measuring 7 meters at Saruca Pasha Tower, demonstrating the fortress’s military might and longevity.

The fortress’s architectural design features three primary entrances that emphasize both practicality and defensibility. Rumeli Hisarı measures 125 by 250 meters and covers 32,000 square meters, making it a significant building along the Bosphorus. Rumeli Hisarı’s strategic location was crucial for controlling Istanbul throughout the Ottoman Empire’s reign.

The Construction and Strategic Importance

Rumeli Hisarı construction began in late March 1452 as part of Fatih Sultan Mehmet’s military operation to control the Bosphorus Strait and prevent hostile naval forces from threatening Constantinople’s siege. The structure’s lumber was procured from Izmit and Karadeniz Ereğli, while the stone was carried from Anatolia, demonstrating the logistical prowess needed for such a large project. The castle was erected in an extraordinarily fast time of ninety days, demonstrating Fatih Sultan Mehmet and his military engineers’ organizational skills and dedication.

The labor force, which numbered around a thousand skilled workers, was made up of masters, laborers, and support people. The fort’s construction covered 60,000 square meters and had a masonry volume of 57,700 cubic meters, demonstrating the scale of the undertaking. Historians such as Dukas and architect EH Ayverdi have underlined the precise planning and execution involved in the fortress’ construction. Fatih Sultan Mehmet personally directed the fortress’s construction atop the Fonea hillside, subsequently renamed Başkesen.

Initially, Rumeli Hisarı served as a military stronghold to prevent attacks. Its function evolved over time, especially with the capture of Istanbul in 1453. Saruca Pasha Tower, for example, was converted into a prison in the years following the capture, adding another layer to the fortress’s changing history.

The Decline and Restoration

Rumeli Hisarı’s military significance faded over the decades. The stronghold was severely damaged by the Great Istanbul Earthquake of 1509, but was swiftly reconstructed. In 1746, a fire destroyed much of the fortress’s wooden infrastructure, forcing significant reconstruction. During Selim III’s rule in the late 18th century, considerable work was done to restore the fortress’s integrity.

By the nineteenth century, the fortress no longer served as a military bastion, and by the late nineteenth century, it had residential areas. In 1876-77, it was stated that 46 dwellings existed within and around the castle walls, indicating a considerable transition in its role from defensive fortification to habitation.

Rumeli Hisarı Today: A Museum and Cultural Venue

Rumeli Hisarı now operates as a historical museum and cultural venue. The fortress’s open-air exhibits include guns, cannonballs, and remnants of the chain that formerly spanned the Golden Horn to prohibit naval access. Though there is no internal exhibition gallery, the garden serves as a place to contemplate on the fortress’s rich history. Visitors can learn about the structure’s history and why it is still a prominent landmark on the Bosphorus.

Rumeli Hisarı not only serves as a museum, but also hosts concerts and theater performances. During rehabilitation work in the 1950s, an open-air theater replaced the demolished Boğazkesen Mosque in the castle. Muhsin Ertuğrul, a well-known theater artist, had a vital role in transforming this facility into an amphitheater. From 1989 to 2008, the theater housed the popular Rumeli Hisarı Concerts, which became one of Istanbul’s most cherished cultural events. The concerts attracted a diverse spectrum of performers, transforming the stronghold into a center of entertainment and cultural expression.

However, the concerts ended in 2008, and in 2009, the Istanbul 3rd Cultural and Natural Heritage Protection Board classified the mosque’s ruins within the castle as a cultural asset. The Istanbul Metropolitan Municipality restored the mosque, completing the Boğazkesen Fetih Mosque in 2015.

Preservation Efforts and Modern Developments

In 2022, the Istanbul Metropolitan Municipality (IMM) began a new repair phase at Rumeli Hisarı. The goal was to preserve and maintain this historically significant monument while also recognizing its importance in Istanbul’s cultural and architectural legacy. As part of these efforts, the stronghold remains a popular cultural destination, with various restaurants catering to both visitors and residents.