Cadmus, in Greek mythology, was a Phoenician prince who slew the Ismenian Serpent, of the spring of Ismene at Thebes, Greece. By the instructions of Athena, he sowed the dragon's teeth in the ground, from which there sprang a race of fierce armed men, called the Spartoi. By throwing a stone among them, he caused them to fall upon one another until only five survived. They joined Cadmus and helped him to build the citadel of Thebes, and became the founders of the noblest families of that city.Cadmus was credited by the ancient Greeks with introducing the original Alphabet or Phoenician alphabet to the Greeks, who adapted it to form their Greek alphabet. Herodotus estimates that Cadmus lived sixteen hundred years before his time, or around 2000 BC. Cadmus was of divine ancestry, the grandson of the sea god Poseidon and Libya on his father's side, and of Nilus (the River Nile) on his mother's side. He was considered a member of the fifth generation of beings following the (mythological) creation of the world.