Final answer:
Italy ruled Constantinople before the Ottomans took over.
Step-by-step explanation:
The country that ruled Constantinople before the Ottomans took over was Italy. In the late 12th century, the Fourth Crusade led to the capture and sack of Constantinople by the Crusaders, who were primarily from Western Europe. The Byzantine Empire was weakened, and a Latin Empire was established with Constantinople as its capital. However, the Latin Empire's rule was short-lived, and in 1261, the Byzantines under the Palaiologos dynasty regained control of Constantinople from the Italians.
Learn more about the history of Constantinople's rulers