Monemvasia, meaning ‘single entrance’, is a fortified city on an isolated rock that lies just off the coast of the southeastern Peloponnesus. It consists of a narrow strip of land by the sea, with cliffs rising vertically, forming a large sloping platform at the top. Originally this was the location of the upper city, but now only the walled lower city exists on the south side of the island, invisible from the mainland. Its only connection with the mainland was an arched bridge, which gave the city its name. The bridge was also the location of its ports, located on each side of the bridge. 

Its Byzantine, Venetian and Ottoman architecture is evidence of its rich, complex history. It has Venetian and Byzantine churches as well as Ottoman architecture, such as a mosque and hamam.  In the Medieval Era, it had periods of prosperous trade and disastrous sacks.  The city was also called Malvasia in Western sources, which also gave its name to a variety of wine.

Architecture
The impressive walls of the lower city are largely Venetian, but they are built on Byzantine foundations. Most of the buildings of the buildings of the city also date to the period of Venetian and Ottoman rule. While not much of the architecture from the Byzantine Era exists, the Church of Hagia Sophia and the Church of the Helkomenos are two noteworthy exceptions. There are also the ruins of other Byzantine churches in the upper and lower city.
The Church of Hagia Sophia in the upper city has a breathtaking location at the edge of a sheer cliff. Originally dedicated to the Hodegetria, it is a domed octagon of the type and scale of Hosios Loukas and Daphni and seems to date to the 12th century. Its frescoes date to the 13th century. 
The Church of the Elkomenos has an important 14th century icon of the Crucifixion that was taken to the Byzantine Museum in Athens and later returned. The church, which has undergone major restorations over time, preserves a carved lintel from around 1000.

Historical Background
Evidence for its early history is scanty. One tradition claims that Monemvasia was found in the late 6th century by people from the region escaping Slavic invaders. After a period of prosperity, it seems to have declined due to Arab raids, particularly once they conquered Crete. It served as a naval station in the wars against the Normans who invaded the area in the 12th century. After Constantinople fell to the Fourth Crusade in 1204, it was the last Byzantine stronghold in the Peloponnese, but it fell to the Frankish lord, William of Villehardouin in 1248 after a two-year siege. 
In 1262 the Byzantines recovered Monemvasia as a result of a treaty and the next year the Byzantine fleet secured control of the surrounding territory. While it was at first the seat of the governor (kephale) of the Byzantine Peloponnese, as the province grew in size, Mystras became its capital. Michael VIII, the Palaiologan emperor who recovered Constantinople, granted certain privileges to Monemvasia and elevated it to a metropolis. The lower city was sacked by the Catalan Company in 1292 and by the Emir of Aydin in 1332. In 1384 Theodore I Palaiologos, despot of the Morea, offered the city to Venice, but the powerful Mamonas family prevented the donation. In 1460 Monemvasia came under papal authority, soon ceded to Venice. The Venetians ceded Monemvasia to the Ottomans in 1540. The Venetians would again control it in 1690, taking control of all of the Peloponnese, yet lost the entire peninsula, including Monemvasia, by 1715.