A second "dark age" started for the Greeks with the arrival of the Ottomans and the collapse of the Byzantine empire. When the Ottomans arrived, two Greek migrations occurred. The first migration entailed the Greek intelligentsia migrating to Western Europe and influencing the advent of the Renaissance. The second migration entailed Greeks leaving the plains of the Greek peninsula and resettling in the mountains. The millet system contributed to the ethnic cohesion of Orthodox Greeks by segregating the various peoples within the Ottoman Empire based on religion.
There were several revolt attempts during the 400 years of the Ottoman occupation none of these revolts met with success. All this changed with the creation of Filiki eteria in 1814 which expanded rapidly and was able to recruite members in all areas of the Greek world. This time the Greek revolution proved succesful, not only because the the timing chosen was right (with the Ottomans weakened and preoccupied with other revolts in their area of influence), but also because this time the Greek revolt aroused widespread sympathy throughout Europe because of the Greek origin of the West's classical heritage. Many wealthy Americans and Western European aristocrats, such as the renowned poet Lord Byron and later the physician Samuel Howe, took up arms to join the Greek revolutionaries.
Greece finally gained its independence and create the first Greek Republic initially in 1830, which later evolved into the Kingdom of Greece in 1832.