Erythraean Sea
The Greeks themselves derived the name from an eponymous persian King Erythras, knowing that the waters so described were deep blue. Modern scholars sometimes attribute the name to the seasonal blooms of the red-hued Trichodesmium erythraeum in the Red Sea. Documents on the Persian Gulf's name describes a story from the  Agatharchides, author of On the Erythraean Sea page 113 saying the Erythrae was son of Myozai a Persian lord which forced  to go to an island because of the attack  by the lions to his cattle ,then  he invited other people to settle in this island, most probably today Qeshm Island or Hormuz Island then  it became lucky island and the name of the Erythraean Sea is related to him.