he Sea of Marmara, also known as the Sea of Marmora or the Marmara Sea, is a small inland sea entirely within the borders of Turkey. It links the Black Sea and the Aegean Sea via the Bosporus and Dardanelles straits, separating Turkeys European and Asian sides. It has an area of 11,350 km2 (4,380 sq mi), and its dimensions are 280 km × 80 km . Its greatest depth is 1,370 m.
The Sea of Marmara is named after the largest island on its south side, called Marmara Island because it is rich in marble.
In classical antiquity, it was known as the Propontis, from the Greek words pro-before and pontos-sea, reflecting the fact that the Ancient Greeks used to sail through it to reach the Black Sea, which they called Pontos.
In Greek mythology, a storm on the Propontis brought the Argonauts back to an island they had left, precipitating a battle in which either Jason or Heracles killed King Cyzicus, who had mistaken them for his Pelasgian enemies.
