Alonissos is an island with great history. In the past, on 16th century there had been precedent names such as Liadromia or Chiliodromia. It has been referred as Alonissos since 1831 and is the only inhabited island in the National Marine Park. According to all the information its first residents were the Dolopes that was a tribe related to Pelasgi. During the Stone Age it seems to have been a lot of movement at the place as afterwards has been found a lot of findings regarding that age such as bone tools in the region of Kokkinokastro. These are possibly the oldest findings indicating human settlement in the Aegean. Additionally at the same Age it is regarded that the island joined the Pelio Peninsula.
In accordance with historic documents in the 478 before Christ the island was concluded into the Athenian Alliance. A few years later about 403 before Christ the Spartans took the proprietary title of the island but a bit later it ended up in the hands of the Athenians. In 146 before Christ Romans took the propriety. Regarding the religious, Alonissos became a Christian island on the 3rd century..
Alonissos seems to have been bloomed while it came under the influence of Phillip of Macedonia when the Macedonians won the Athenians during a war that burst out between them. Although it seems to has been flourished as a part of the Byzantine Empire not only economically but also culturally, as is witnessed by the monuments of the time such as churches, monasteries and fortifications. The islands that surround Alonissos were monastic centres of great importance and many of these still exist and belong today to the monastery of Megesti Lavra of the mountain Athos.
When occurred the fact of the capture of Constantinople by the Crusaders, the islands became the property of Western feudal lords. In 1453 the Ottomans destroyed the Byzantine Empire and the area was taken over by the Venetians. After all these the island had even more difficult times as in 1538 accepted the raids of the Turkish fleet under the command of the pirate Barbarossa. In the 16th century and while the Greek people were under the ottoman occupation the island was rein habited by Greeks and in 1821 the Greek’s uprising against the Turks in the pre-Revolutionary had as a result a few years later that is in 1830 to be signed the “Treaty of London”. According with that the Northern Sporades and the present area of the Park were included in the newly established Hellenic State.