The Byzantine Empire or Byzantium is the term conventionally used since the 19th century to describe the ethnic and Greek-speaking Roman Empire of the Middle Ages, centered on its capital of Constantinople. As the direct continuation of the Roman Empire, Byzantium survived the fall of the Western Roman Empire during Late Antiquity, and continued to function until its conquest by the Ottoman Empire in 1453. During this time, many different imperial dynasties ruled over the empire; in the context of Byzantine history, the period c.1185 – c.1204 AD was under the Angeloi dynasty.