In 1470 Mehmet the Conqueror further strengthened the ancient portal by building three towers of his own, linked by curtain walls to the four Byzantine towers flanking the Golden Gate.
The portal was strengthened during a time of war.
mnli hypothesis: The portal was strengthened during a time of war. premise: In 1470 Mehmet the Conqueror further strengthened the ancient portal by building three towers of his own, linked by curtain walls to the four Byzantine towers flanking the Golden Gate.