The Greek islands, or Aegean Islands as they are more commonly known, were part of the Insulae province in the Diocese of Asia during the medieval and Byzantine eras. At that time, Greece was subject to a large amount of foreign invasions. However, the peninsula remained prosperous and economically active.
Greece and the Aegean Islands were divided into provinces by the Byzantine Empire during the second and third centuries. In the fourth and fifth centuries, they were under invasion by the Slavs and many areas were settled by the group.The whole story can be found at http://greece.greekreporter.com/2013/07/04/no-ships-for-northern-aegean-islands-this-summer/ They were defeated by the seventh century. The Bulgarians were the next invaders in the ninth century. Once this threat expired, Greece as a whole continued to grow and become prosperous. In the late 11th century, the Normans and the Franks began to eye the Greek region. It was eventually divided by the Crusaders after the Fourth Crusade. By the 12th century, Michael VIII had regained the Aegean Islands from the Crusader holdings. In the 14th and 15th centuries, the Ottoman Empire invaded and gained control of much of Greece and the Aegean Islands.
