Conceived and built between 1451 and 1452 CE on the orders of Sultan Mehmed II, the complex was commissioned in preparation for a planned Ottoman siege on the then-Byzantine city of Constantinople,[1] with the goal of cutting off maritime military and logistical relief that could potentially come to the Byzantines' aid by way of the Bosphorus Strait, hence the fortress's alternative name, "Boğazkesen", i.e. "Strait-cutter" Castle.

Its older sister structure, Anadoluhisari ("Anatolian Fortress"), sits on the opposite banks of the Bosporus, and the two fortresses worked in tandem during the final siege to throttle all naval traffic along the Bosphorus, thus helping the Ottomans achieve their goal of making the city of Constantinople (later renamed Istanbul) their new imperial capital in 1453.

After the Ottoman conquest of the city, Rumelihisarı served as a customs checkpoint and occasional prison, notably for the embassies of states that were at war with the Empire.

Today, the fortress is a popular museum open to the public, and further acts as an open-air venue for seasonal concerts, art festivals, and special events.

The necessity of a strategic fortress on the Bosphorus was well known to the Ottomans, who had started in the late 14th century to harbor intentions of capturing the city of Constantinople as a new capital for their then-nascent Empire.

In a previous Ottoman attempt to conquer the city, Sultan Murad II (1421–44, 1446–51) had encountered difficulties due to a blockade of the Bosphorus by the Byzantine fleet.

This move by the Byzantines was seen as pretext for war and thus Mehmed proceeded with the plans of conquering the Constantinopole by first commissioning the construction of a large fortress that would be used to control all sea traffic along the Bosphorus, and would work together with the older Anadoluhisari (Anatolia Fortress) on the strait to prevent any possible maritime aid from reaching Constantinople during the final Ottoman siege of the city in 1453, particularly from Genoese colonies along the Black Sea, such as Caffa, Sinop and Amasra.

The site for the new fortress was quickly decided to be the narrowmost point of the Bosphorus, where the strait is a mere 660 meters (2,170 ft) wide.

This tall, hilltop site on the strait's European banks not only made for easier control of the waterway, but also had the advantage of being situated directly across the Anadoluhisarı ("Anatolian Fortress") on the Anatolian (i.e. Asian) banks of the Bosphorus; an older Ottoman fortress built between 1393 and 1394 by Sultan Bayezid I.

Conical wooden roofs covered with lead originally crowned the towers, although these no longer survive today.

In 1953, on the orders of President Celal Bayar, the inhabitants were relocated and extensive restoration work began on 16 May 1955, which lasted until 29 May 1958.