Rumeli Hisari Fortress was also named ‘throat cutter’, designed as it was to throttle Byzantine trade and reinforcements before the siege of the great city.
Visiting Rumeli Hisari Fortress
To get to the fortress from the centre of Byzantium is less than 3 hours walk, about 13km. It’s an easy drive too or there is the option to get one of the ferries that stop either side of Sultan Mehmet Bridge and walk from there. Rumeli Hisari Fortress is a major tourist attraction in Istanbul and also a source of National pride akin to the White Tower in London.
It’s actually a really sad building historically. The structure is magnificent, strong and imposing but that fact it is built so close to old Byzantium and on the European shore (hence ‘Rumeli’ or ‘Roman’) shows how pathetic the city was by this stage.
The castle is open every day except Mondays and naturally has superb views across the Bosphorus.
My Experience
This was our second visit to the tower (in 2012) and it was on our 2008 visit that we went inside. This was taken from a ferry trip up the Bosphorus and gives an excellent idea of how the fort strangled any Byzantine trade with the Black Sea cities. The first couple of pictures are of the earlier Anatolian Castle, built on the opposite bank and closed to the public. The trip is covered in detail on my travel blog here.
Rumeli Hisari Fortress Photo Gallery
The Anatolian Castle 
The Anatolian Castle 
Rumeli Hisari Fortress 
Rumeli Hisari Fortress 
Rumeli Hisari Fortress
These next photos were taken in the dim and distant past of 2008 and they were not taken in RAW so these are pretty much unedited jpgs. I’d like to think my own skill in photography has moved on since then too so these may not be ideal pictures. Sorry!
History
Rumelihisarı Castle, locally known just as Rumelihisarı, lies in the Sarıyer district of the city of Istanbul, on the European side of the Bosphorus Strait in the province of Istanbul in Turkey.
Rumelihisarı translates back to Roman (Rumeli-) fortress (-hisarı). Originally it was called Boğazkesen, which translates back to ‘Strait-cutter’.
The first fortication at this site was a Roman fort that was later used as a prison by the Byzantines and the Genoese. Later on it was transformed into a monastery.
Rumelihisarı Castle was built in 1452 in a record time of 4.5 months by the Ottoman Sultan Mehmed II, in preparation for his siege of the then-Byzantine city of Constantinople, at the narrowest point of the Bosphorus. It was built directly opposite Anadoluhisarı Castle on the Asian side of the Bosphorus, built by Sultan Bayezid I in the 1390’s.
Built on a hilly slope, with the use of lots of building materials from Roman ruins in the area, the castle got a very irregular ground plan with 3 formidable main towers, 3 gates and 12 secondary watchtowers connected by meandering curtain walls.
After being completed the castle was garrisoned with a battalion of 400 Janssaries and large cannons were placed in the large tower nearest the waterfront. The 2 castles worked in tandem in 1453 to block all maritime traffic along the Bosphorus, thus aiding the Ottomans during their siege of Constantinople.
After Constantinople had fallen at the end of a 53-day siege in 1453, Rumelihisarı served as a customs checkpoint and occasional prison, notably for the embassies of states that were at war with the Empire. After suffering extensive damage in the Great Earthquake of 1509, the structure was repaired.
In 1746 it was damaged by fire. Later that century it lost its strategic importance after several new fortifications (i.a. Garipçe, Poyrazköy and Rumelifeneri castles) were built at the entrance to the Bosphorus from the Black Sea.
In the 19th century it was abandoned and a small residential neighborhood grew up within the castle’s walls. During the late 1950’s the neighborhood was removed and the castle restored. Since then it has been a museum.
References
The Istanbul museum site with full opening information is here.
There is a fascinating guide to the castle and its wider geopolitical context on the Peter Sommer tour site here.
The history above is copied from the castles.nl site here.