Political relationships between Byzantine Empire, Latin sovereigns in Romania and the Turks (1204-1453)

After the Fourth Crusade, Byzantine Empire collapsed and a new era started in the history of the Romania. Several Latin sovereigns and Roman states which were heirs of the Byzantium Empire established in the Byzantine lands. In the great part of the thirteenth century, Roman states endeavored to accomplish restoration of the Byzantine Empire and Latins aimed to restrain their intentions. But the Empire of Nicaea, which recaptured Constantinople from Latins 57 years later, was the winner of the struggle. On the other hand Byzantine Empire continued to struggle with Latins, lost its territories in western Anatolia to Turks in the early years of fourteenth century. Because negligence and bad policies of the empire led to establishment of the various Turkish Emirates in western Anatolia. These Emirates not only conquered the Byzantine lands but also they successfully attacked the ports and the cities in Romania belonging to Latins. Especially emirates of Menteshe and Aydin pioneered the so-called Turkish invasions. Byzantine Empire, weakened by both western and eastern rivals, completely fell into a decline. So that it became a state that depended on its allies to withstand against its enemies. When Ottoman State begun to invade European lands of the empire in the mid-fourteenth century, Byzantine Empire has no power to resist their invasion. In the end, Byzantine Empire gradually lost its territories to Ottoman State until the mid-fifteenth century and it was reduced to the level of a vassal state. The Empire finally collapsed after the final fall of Constantinople in 1453.