Kos in the context of "Ptolemy XII Auletes"

The Aegean Sea is an elongated embayment of the Mediterranean Sea between Europe and Asia. It is located between the Balkans and Anatolia, and covers an area of some 215,000 km (83,000 sq mi). In the north, the Aegean is connected to the Marmara Sea, which in turn connects to the Black Sea, by the straits of the Dardanelles and the Bosphorus, respectively. The Aegean Islands are located within the sea and some bound it on its southern periphery, including Crete and Rhodes. The sea reaches a maximum depth of 2,639 m (8,658 ft) to the west of Karpathos. The Thracian Sea and the Sea of Crete are main subdivisions of the Aegean Sea.

The Aegean Islands can be divided into several island groups, including the Dodecanese, the Cyclades, the Sporades, the Saronic islands and the North Aegean Islands, as well as Crete and its surrounding islands. The Dodecanese, located to the southeast, includes the islands of Rhodes, Kos, and Patmos; the islands of Delos and Naxos are within the Cyclades to the south of the sea. Lesbos is part of the North Aegean Islands. Euboea, the second-largest island in Greece, is located in the Aegean, despite being administered as part of Central Greece. Nine out of twelve of the Administrative regions of Greece border the sea, along with the Turkish provinces of Edirne, Çanakkale, Balıkesir, İzmir, Aydın and Muğla to the east of the sea. Various Turkish islands in the sea are Imbros, Tenedos, Cunda Island, and the Foça Islands.

The Dodecanese (UK: /ˌdoʊdɪkəˈniːz/, US: /doʊˌdɛkəˈniːz/; Greek: Δωδεκάνησα, Dodekánisa [ðoðeˈkanisa], lit. 'twelve islands') are a group of 15 larger and 150 smaller Greek islands in the southeastern Aegean Sea and Eastern Mediterranean, off the coast of Anatolia, of which 26 are inhabited. This island group generally defines the eastern limit of the Sea of Crete. They belong to the wider Southern Sporades island group.

Rhodes has been the area's dominant island since antiquity. Of the others, Kos and Patmos are historically the most important; the remaining 12 are Agathonisi, Astypalaia, Halki, Kalymnos, Karpathos, Kasos, Leipsoi, Leros, Nisyros, Symi, Tilos, and Megisti. Other islands in the chain include Alimia, Arkoi, Farmakonisi, Gyali, Kinaros, Levitha, Marathos, Nimos, Pserimos, Saria, Strongyli and Syrna.

The Second Athenian League was a maritime confederation of Greek city-states that existed from 378 to 355 BC under the leadership (hegemony) of Athens. It is sometimes referenced as the second Athenian Empire, despite operating as a confederation. The alliance represented a partial revival of the Delian League, which had been disbanded in 404 BC following the defeat of Athens in the Peloponnesian War. The new League was centered in the Aegean and included over 60 states, among which were Kos, Mytilene, Rhodes, and Byzantium. It was primarily formed as a defensive alliance against Sparta and secondly the Persian Empire. The new League's main objective was to preserve peace in Greece and counterbalance Sparta's growing hegemony and aggression. The League largely revived Athenian influence in the Greek world, reestablishing it as the strongest naval power in the eastern Mediterranean. This time, Athens made conscious efforts to avoid the strict terms that had eventually rendered the previous Delian League unpopular. The alliance lasted until 355 BC, when most of the allied cities became independent following the Social War that broke out in 357 BC.

Kalymnos (Greek: Κάλυμνος; Modern Greek pronunciation: [ˈkalimnos]) is a Greek island and municipality in the southeastern Aegean Sea. It belongs to the Dodecanese island chain, between the islands of Kos (south, at a distance of 12 km (7 mi)) and Leros (north, at a distance of less than 2 km (1 mi)): the latter is linked to it through a series of islets. Kalymnos lies between two and five hours away by sea from the island of Rhodes.

In 2021 the island had a population of 17,752, making it the third most populous island of the Dodecanese, after Kos and Rhodes. It is known in Greece for the affluence of much of its population, and also stands as both the wealthiest member of the Dodecanese and one of the wealthiest Greek islands overall. The Municipality of Kalymnos, which includes the populated offshore islands of Pserimos, Telendos, Kalolimnos, and Pláti, as well as several uninhabited islets, has a combined land area of 134.544 square kilometres (51.948 sq mi) and a total population of 17,752 inhabitants (2021).

Nisyros, also spelled Nisiros (Greek: Νίσυρος, romanized: Nísyros; Modern Greek pronunciation: [ˈnisiros]), is a volcanic Greek island and municipality located in the Aegean Sea. It is part of the Dodecanese group of islands, situated between the islands of Kos and Tilos.

Its shape is approximately round, with a diameter of about 8 km (5 mi), and an area of 41.6 km (16.062 sq mi). Several other islets are in the direct vicinity of Nisyros, the largest of which is Gyali, with a population of 22 citizens. The Municipality of Nisyros includes Gyalí, as well as uninhabited Pacheiá, Pergoússa, Kandelioussa, Ágios Antónios, and Strongýli. It has a total land area of 50.055 km (19.326 sq mi) and a total population of 1,048 inhabitants (2021).

Tílos (Greek: Τήλος; Ancient Greek: Τῆλος, romanized: Telos) is a small Greek island and municipality located in the Aegean Sea. It is part of the Dodecanese group of islands, and lies midway between Kos and Rhodes. In 2021, the island had a population of 746 people. Along with the uninhabited offshore islets of Antitilos and Gaidaros, it forms the Municipality of Tilos, which has a total land area of 64.525 square kilometres (24.913 sq mi). Tilos is part of the Rhodes regional unit.

Popularly, Telos was the son of Helios and Halia, the sister of the Telchines. He came to the island in search of herbs to heal his ill mother, and later returned to found a temple to Apollo and Neptune. However, Telos (Telo or Tilo) does not appear in Greek mythology and the name probably has an unknown pre-Hellenic origin. Pliny the Elder notes that in antiquity Telos was known as Agathussa (Αγαθούσσα) (also Agathusa and Agathousa). In the Middle Ages, it was known by the Italian as Episcopio, either because it was a Bishop Seat or because its position as Vantage Point. The island has also been called in Turkish İlyaki and in modern Italian Piscopi.

Gyali (Greek: Γυαλί "glass", also spelled Giali or Yali, pronounced [ʝaˈli]) is a Greek volcanic island in the Dodecanese, located halfway between the south coast of Kos (Kardamaina) and Nisyros. It consists of rhyolitic obsidian lava domes and pumice deposits (which are mined in huge quantities). No historical eruptions are known, but the most recent pumice eruptions overlie soils containing pottery and obsidian artifacts from the Neolithic period (10,000–4,500 BC). The island has two distinct segments, with the northeastern part almost entirely made of obsidian and the southwestern part of pumice. These are connected by a narrow isthmus and beach made of modern reef sediments. Anciently, the island was known as Istros (Ancient Greek: Ἴστρος).

Pserimos (Greek: Ψέριμος Δωδεκανήσου) is a small Greek island in the Dodecanese chain, lying between Kalymnos and Kos in front of the coast of Turkey. It is part of the municipality of Kálymnos, and reported a population of 80 inhabitants at the 2011 census.

The main industry is tourism, with Greek and other European holidaymakers attracted by its remote location and beaches. There are a number of taverns, some of which offer accommodation.

Kos (Greek: Περιφερειακή ενότητα Κω) is one of the regional units of Greece. It is part of the region of South Aegean. The regional unit covers the islands of Kos, Nisyros and several smaller islands in the Aegean Sea.