The island's official name, Megisti (Μεγίστη) means "biggest" or "greatest", but at only 11.98 km2 (4.626 sq mi) in area, it is the smallest of the Dodecanese.

It is the largest island of the homonym archipelago comprising the islands and islets of Agios Georgios, Agrielaia, Voutsakia, Megalo Mavro Poini, Mikro Mavro Poini, Polifados Ena, Polifados Dio, Ro, Savoura, Stroggili, Tragonera, Psomi and Psoradia.

[14] There are many islets in this area; Volos, near Kalkan (in Greek Kalamaki), Ochendra, Furnachia, Prassonisi, Ro, Tragonera, Marathi, Strongyli, Dhassia, Alimentaria, Kekova and Psomi besides many rocks and cliffs.

[15] The most important among these islets is Kekova (also named Caravola), not inhabited, which has an area of 4.5 square kilometres (1.7 sq mi) and faces the Turkish village of Kaleköy (Simena in antiquity).

On the opposite side of the harbour one has a good view from this vantage of Pera Meria, the western quay, and the monasteries of Profitis Ilías and Aghia Triadha, the former now an army base.

[15] Ascending the steps on the eastern side of the town, one reaches the suburb of Horafia, where there is a square surrounded by the Church of St. George (1906), with a high dome of Byzantine type, and the Cathedral of Saints Constantine and Helena (1835).

[15] Carved on the base of the castle there is also a Doric inscription, dating back to the 4th or 3rd centuries BC, with references to Megiste (the ancient name of Kastellorizo) and its dependence on Rhodes.

[25] In addition, inscriptions found at the foot of the Knight's castle confirm that during the Hellenistic period the island was ruled by Rhodes, and formed part of its Peraia.

The three towers of Kastellorizo, Ro and Strongyli comprise the main links in a dense network of watchtowers constructed by the Rhodians during the Hellenistic period, to control the sea routes and the coast.

[4] Ten years later it was conquered by Alfonso V of Aragon, king of Naples, who in 1461 rebuilt the castle and dispatched a Catalan governor.

[4] According to the Ottoman General Census of 1881/82-1893, the kaza of Kastellorizo (Meyis) had a total population of 4,871, consisting of 4,635 Greeks, 225 Muslims, 6 Jews and 5 foreign citizens.

[17] In August 1913, the Greek government sent from Samos a provisional governor supported by gendarmes, but in early 1914 in Florence it was decided that the island would be returned to the Ottoman Empire.

During World War I, while the Kingdom of Greece was still neutral, French Navy warships led by the cruiser Jeanne d'Arc occupied Kastellorizo on 28 December 1915 at the behest of local inhabitants who feared Ottoman reprisals.

[17] Ottoman shore batteries responded to the French occupation by shelling the island in 1917, which resulted in the sinking of the British Royal Navy seaplane carrier HMS Ben-my-Chree.

During the Second World War, on 25 February 1941, in the course of Operation Abstention, British Commandos occupied the island, but Italian forces from Rhodes recaptured it some days later.

In 2011, the French ship Dignité-Al Karama, the only member the Freedom Flotilla II that managed to approach Gaza, refueled at Kastellorizo.

[17] Its sailing ships traded products from Anatolia (coal, timber, valonia, pine bark) for Egyptian goods (rice, sugar, coffee, tissues and yarns), and carried Anatolian cereals to Rhodes and Cyprus.

[17] After 1908, the decay of the island's economy set in, accelerated by the decline of the Ottoman Empire and the population exchange between Greece and Turkey in 1923.

[17] The engagement, which was decided by the parents, and the wedding, which lasted 15 days, occurred through prescribed and curious ceremonies, having symbolic and poetic meaning.

[16] Weddings were celebrated on Sunday, in the church of Agios Konstantinos, and an announcement on the main square invited the whole city to participate.

Also baptisms and funerals (with mourning women, or praeficae, and a dish with oil and wine crushed on the coffin) had well-established rituals.

[16] On December 31 and on New Year's Day, groups of children carrying small cardboard boats adorned with ribbons and small flags go around visiting houses, stores and coffee shops, singing songs with good wishes and receiving coins and wheat cakes, while the elderly exchange visits.

[16] On the morning of Agios Basilios day, coming back from Liturgy, the men customarily throw a pomegranate hard against the walls of their homes, wishing for abundance and happiness for their family.

[16] On Easter Monday the whole population gathers in the main square, and they remain there the whole day eating, drinking and singing.

[16] On May 1, at dawn, all the girls of the island, in groups, each one carrying a jar, went to get water outside of town, but they were not allowed to speak a single word during the route.

When a girl became engaged, she filled a crystal carafe with it and brought it to her future mother-in-law, who gave her in return a special cake and an odd number of gold coins.

She drew signs of the cross on the body of the child with a thurible filled with embers and branches of the olive tree which had been gathered in the church on Palm Sunday, pronouncing the following words: "Christ came: then he laid down his stick and chased away the snake and the bad neighbor from our home".

After this exorcism, the woman would throw the content of the thurible into a bucket filled with water, and then count the pieces of wood which did not burn.

[16] Kastellorizo is twinned with: In the 1961 film The Guns of Navarone, a saboteur team led by Anthony Quayle is briefed on its mission at Castelrosso.