Marmara Sea
The Sea of Marmara (Turkish: Marmara denizi, Modern Greek: Μαρμαρα̃ Θάλασσα or Προποντίδα) (also known as the Sea of Marmora or the Marmara Sea) is an inland sea that separates the Black Sea from the Aegean Sea (thus the Asian part of Turkey from its European part) by Bosporus and Dardanelles.
There are two major island groups known as Prince and Marmara islands. The latter group is rich in sources of marble and gives the sea its name (marmaros is the Greek word for marble).
Propontis (Προποντίς, -ίδος) was the ancient map, see: Geography of Turkey
