The Fourth Crusade weakened Byzantine control of the area, and it was eventually conquered by the Ottoman Empire, with the exception of Crete, which was a Venetian colony until 1669.

The rocks making up the floor of the Aegean are mainly limestone, though often greatly altered by volcanic activity that has convulsed the region in relatively recent geologic times.

[3] Notable cities on the Aegean coastline include Athens, Thessaloniki, Volos, Kavala, and Heraklion in Greece, and İzmir and Bodrum in Turkey.

Issues include the delimitation of territorial waters, national airspace, exclusive economic zones, and flight information regions.

According to the International Hydrographic Organization, the limits of the Aegean Sea as follows:[9] Aegean surface water circulates in a counterclockwise gyre, with hypersaline Mediterranean water moving northward along the west coast of Turkey, before being displaced by less dense Black Sea outflow.

According to the Köppen climate classification, most of the Aegean is classified as Hot-summer Mediterranean (Csa), with hotter and drier summers along with milder and wetter winters.

Before that time, at the peak of the last ice age (about 18,000 years ago) sea levels everywhere were 130 metres (430 ft) lower, and there were large well-watered coastal plains instead of much of the northern Aegean.

Their syllabic script, the Linear B, offers the first written records of the Greek language and their religion already included several deities that can also be found in the Olympic Pantheon.

Mycenaean Greece was dominated by a warrior elite society and consisted of a network of palace-centered states that developed rigid hierarchical, political, social and economic systems.

During the Greek Dark Ages, writing in the Linear B script ceased, vital trade links were lost, and towns and villages were abandoned.

Each of them had brought the surrounding rural areas and smaller towns under their control, and Athens and Corinth had become major maritime and mercantile powers as well.

In the 8th and 7th centuries BC many Greeks migrated to form colonies in Magna Graecia (Southern Italy and Sicily), Asia Minor and further afield.

Cassander became king of the Hellenistic kingdom of Macedon, which held territory along the western coast of the Aegean, roughly corresponding to modern-day Greece.

Although the Rashidun Caliphate did not manage to obtain land along the coast of the Aegean Sea, its conquest of the Eastern Anatolian peninsula as well as Egypt, the Levant, and North Africa left the Byzantine Empire weakened.

During the 820s, Crete was conquered by a group of Berbers Andalusians exiles led by Abu Hafs Umar al-Iqritishi, and it became an independent Islamic state.

Under Presian and his successor Boris I, the Bulgarian Empire managed to obtain a small portion of the northern Aegean coast.

The Second Bulgarian Empire achieved similar success along, again, the northern and western coasts, under Ivan Asen II of Bulgaria.

The Venetians created the maritime state of the Duchy of the Archipelago, which included all the Cyclades except Mykonos and Tinos.

The Empire of Nicaea, a Byzantine rump state, managed to affect the Recapture of Constantinople from the Latins in 1261 and defeat Epirus.

By the late 14th century, the Byzantine Empire had lost all control of the coast of the Aegean Sea and could exercise power around their capital, Constantinople.

The Ottoman Empire held a presence over the sea for over 500 years until its dissolution following World War I, when it was replaced by modern Turkey.

In the Italo-Turkish War of 1912, Italy captured the Dodecanese islands, and had occupied them since, reneging on the 1919 Venizelos–Tittoni agreement to cede them to Greece.

In ancient times, navigation through the sea was easier than travelling across the rough terrain of the Greek mainland, and to some extent, the coastal areas of Anatolia.

Piraeus bi-annually acts as the focus for a major shipping convention, known as Posidonia, which attracts maritime industry professionals from all over the world.

Piraeus is currently Greece's third-busiest port in terms of tons of goods transported, behind Agioi Theodoroi and Thessaloniki.

[28] Fish captured include sardines, mackerel, grouper, grey mullets, sea bass, and seabream.

For demersal fisheries, the catches from the northern and southern Aegean area groupings are dominated by grey mullets and pickerel (Spicara smaris) respectively.

[clarification needed] Overfishing and habitat destruction is also a concern, threatening grouper, and seabream populations, resulting in perhaps a 50% decline of fish catch.

[32] A total of five UNESCO World Heritage sites are located the Aegean Islands; these include the Monastery of Saint John the Theologian and the Cave of the Apocalypse on Patmos,[33] the Pythagoreion and Heraion of Samos in Samos,[34] the Nea Moni of Chios,[35] the island of Delos,[36] and the Medieval City of Rhodes.

[44] Greece and Turkey both take part in the Blue Flag beach certification programme of the Foundation for Environmental Education.