Constantinople (see other names) was the capital of the Roman Empire, and later, the Eastern Roman Empire (also known as the Byzantine Empire; 3301204 and 12611453), the Latin Empire (12041261), and the Ottoman Empire (14531922). Following the Turkish War of Independence, the Turkish capital then moved to Ankara. Officially renamed Istanbul in 1930, the city is today the largest city and financial centre of the Republic of Turkey (1923present). It remains the largest city in Europe.

In 324, the ancient city of Byzantium was renamed "New Rome" and declared the new capital of the Roman Empire by Emperor Constantine the Great. On 11 May 330, it was renamed to Constantinople, and dedicated to Constantine. Constantinople is generally considered to be the center and the "cradle of Orthodox Christian civilization". From the mid-5th century to the early 13th century, Constantinople was the largest and wealthiest city in Europe. The city became famous for its architectural masterpieces, such as Hagia Sophia, the cathedral of the Eastern Orthodox Church, which served as the seat of the Ecumenical Patriarchate, the sacred Imperial Palace where the Emperors lived, the Hippodrome, the Golden Gate of the Land Walls, and opulent aristocratic palaces. The University of Constantinople was founded in the fifth century and contained artistic and literary treasures before it was sacked in 1204 and 1453, including its vast Imperial Library which contained the remnants of the Library of Alexandria and had 100,000 volumes. The city was the home of the Ecumenical Patriarch of Constantinople and guardian of Christendom's holiest relics such as the Crown of thorns and the True Cross.

Constantinople was famed for its massive and complex fortifications, which ranked among the most sophisticated defensive architecture of Antiquity. The Theodosian Walls consisted of a double wall lying about 2 kilometres (1.2 mi) to the west of the first wall and a moat with palisades in front. Constantinople's location between the Golden Horn and the Sea of Marmara reduced the land area that needed defensive walls. The city was built intentionally to rival Rome, and it was claimed that several elevations within its walls matched Rome's 'seven hills'. The impenetrable defenses enclosed magnificent palaces, domes, and towers, the result of prosperity Constantinople achieved as the gateway between two continents (Europe and Asia) and two seas (the Mediterranean and the Black Sea). Although besieged on numerous occasions by various armies, the defenses of Constantinople proved impenetrable for nearly nine hundred years.

In 1204, however, the armies of the Fourth Crusade took and devastated the city and, for several decades, its inhabitants resided under Latin occupation in a dwindling and depopulated city. In 1261 the Byzantine Emperor Michael VIII Palaiologos liberated the city, and after the restoration under the Palaiologos dynasty, it enjoyed a partial recovery. With the advent of the Ottoman Empire in 1299, the Byzantine Empire began to lose territories and the city began to lose population. By the early 15th century, the Byzantine Empire was reduced to just Constantinople and its environs, along with Morea in Greece, making it an enclave inside the Ottoman Empire. The city was finally besieged and conquered by the Ottoman Empire in 1453, remaining under its control until the early 20th century.

An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in size from those that are so weak that they cannot be felt to those violent enough to propel objects and people into the air, and wreak destruction across entire cities. The seismicity, or seismic activity, of an area is the frequency, type, and size of earthquakes experienced over a particular time period. The word tremor is also used for non-earthquake seismic rumbling.

At the Earth's surface, earthquakes manifest themselves by shaking and displacing or disrupting the ground. When the epicenter of a large earthquake is located offshore, the seabed may be displaced sufficiently to cause a tsunami. Earthquakes can also trigger landslides and, occasionally, volcanic activity.

In its most general sense, the word earthquake is used to describe any seismic event—whether natural or caused by humans—that generates seismic waves. Earthquakes are caused mostly by rupture of geological faults but also by other events such as volcanic activity, landslides, mine blasts, and nuclear tests. An earthquake's point of initial rupture is called its hypocenter or focus. The epicenter is the point at ground level directly above the hypocenter.