Following Zeno of Rhodes, who wrote the history of his home in the first half of the second century B.C.,[80] Diodorus tells us: The king of the Phenicians, Agenor, bade his son Cadmus seek his sister Europa,[81] who had disappeared, and bring back the maiden, or not return himself to Phoenicia. Overtaken by a violent storm, Cadmus vowed a shrine to Poseidon. He was saved, and landed on the island of Rhodes, where the inhabitants worshipped before all other gods the sun, who had here begotten seven sons and among them Makar. Cadmus set up a temple in Rhodes to Poseidon, as he had vowed to do, and left behind Phenicians to keep up the service; but in the temple which belonged to Athena at Cnidus in Rhodes he dedicated a work of art, an iron bowl, which bore an inscription in Phenician letters, the oldest inscription which came from Phoenicia to the Hellenes. From Rhodes Cadmus came to Samothrace, and there married Harmonia. The gods celebrated this first marriage by bringing gifts, and blessing the married pair to the tones of heavenly music.[82] Ephorus says that Cadmus carried off Harmonia while sailing past Samothrace, and hence in that island search was still made for Harmonia at the festivals.[83] Herodotus informs us that Cadmus of Tyre, the son of Agenor, in his search for Europa, landed on the island of Thera, which was then called Callisto, and there left behind some Phenicians, either because the land pleased him or for some other reason. These Phenicians inhabited the island for eight generations before Theras landed there from Lacedæmon. The rest went to the island of Thasos and there built a temple to Heracles, which he had himself seen, and the city of Thasos. This took place five generations before Heracles the son of Amphitryon was born. After that Cadmus came to the land now called Boeotia, and the Phenicians who were with him inhabited the land and taught the Hellenes many things, among others the use of writing, "which as it seems to me the Hellenes did not possess before. They learnt this writing, as it was used by the Phenicians; in the course of time the form of the letters changed with the language. From these Phenicians the Ionians, among whom they dwelt, learnt the letters, altered their form a little, and extended their use. As was right, they called them Phenician letters, since the Phenicians had brought them into Greece. I have myself seen inscriptions in Cadmeian letters (_i.e._ from the time of Cadmus) in the temple of Ismenian Apollo at Thebes."[84] According to the narrative of Hellanicus, Cadmus received an oracle, bidding him follow the cow which bore on her back the sign of the full moon, and found a city where she lay down. Cadmus carried out the command, and when the cow lay down wearied, where Thebes now stands, Cadmus built there the Cadmeia (the citadel of Thebes).[85] According to the statement of Pherecydes Cadmus also built the city of Thebes.[86]