In the year 1453 the major incident that happened was the Ottoman Turks conquered Constantinople. The correct option among all the options given in the question is option "b". The Byzantine Empire ended with the fall of Constantinople. The capital of the Byzantine Empire was captured by the Ottoman conqueror Sultan Mehmed II. Curtains came down on the great Byzantine empire and the rule of the Ottoman Turks started in Constantinople. This was a major historical event that occurred during the year 1453.