Cadmus was a unique character among Greek heroes. Everyone is unique, it's common knowledge, but Cadmus was the only one among accepted and worshiped Greek heroes who was of different origin. Despite having Poseidon as his grandfather, it is said that first he was originally a resident of ancient Phoenician civilization and came to Greece in search of his sister Europe who was abducted by the king of the gods. Cadmus also happened to become the founder of Thebes, after the consultation with the Delphic Oracle who told him to abandon his search for his sister and rather follow his own path. He was also a great warrior and a born leader, not to mention that he was very well educated. And it is also said that, from Phoenicia, Cadmus brought the first alphabetic writing to the Greeks which consisted of sixteen letters. It was the very first foundation of alphabet in the western world that we know today.
Cadmus is depicted as a young man, either fighting a guardian dragon with a spear or sowing the dragon's teeth in his quest of founding Thebes. There is also a picture of Cadmus with his wife Harmonia where they are depicted as serpents.
Searching for his sister Europa
Cadmus was a son of king Agenor and queen Telephassa of Tyre and had two brothers and a sister. His myth begins when Zeus fell in love and travelled to Phoenician lands to seduce Cadmus' sister Europa. Zeus transformed himself into a white bull, in order to charm her and Europe was fascinated by his beauty. The bull approached slowly and gently, with the intention to gain Europa's trust. Once the trust was established, she put flowers around the bull's neck and climbed on his back. Without hesitation, Zeus, disguised in a white bull, went into the sea and started swimming without a pause. He brought her to Crete and revealed his true identity. Europa was frightened but also reassured by Zeus that she is safe and that her royal bloodline will not end. In the meantime, king Agenor was devastated by daughter's mysterious disappearance and dispatched his sons on a mission to find her. The king commanded his sons never to return without his beloved daughter. Their mother Telephassa also accompanied them in this quest, mostly, because she could not stop thinking about her daughter. Together they had searched and covered a lot of ground, but didn't find any clue of her disappearance. Unable to find their sister, all of the brothers eventually stopped looking and settled in their new areas, founding new cities. However, Cadmus' path was a bit different from his brothers. With the restless desire of his mother Telephassa, who joined Cadmus, they continued searching for her until they had been forced to eventually settle in Thrace. Telephassa soon died there of grief and sorrow at the loss of her daughter.
After the burial ceremony, Cadmus travelled to the oracle of Delphi to ask for guidance of finding his sister. He was instructed to follow the cow with a white, full moon-shaped spot on either flank and to settle a city where the cow would stop for rest. Cadmus, determined to follow the guidance, came from the Oracle and sought the described cow just few meters away. He followed her path which led to Boeotia, more precisely to the Cephisus river where the cow lied on the ground due to fatigue. Cadmus knew this was the place and, in order to honor the establishment of the city, he wanted to sacrifice the cow to Athena. While preparing the ceremony, he sent his followers to draw some water from a nearby spring. This, however, was not an ordinary spring. It was the spring of Ares and while they were filling their vessels, a serpentine creature emerged and slaughtered them. When they didn't come back, Cadmus sent more men for water. But they were also killed by the guardian of the spring. When none of the men, that he had sent for water, came back, he went looking for them and soon faced the horrific monster with a crest shaped head and gold shining venomous teeth. Driven by rage and revenge, he managed to slay the beast and avenged his followers. He also finally got some water for the cow's purification. When he sacrificed the cow to Athena, the goddess told him to get the dragon's teeth of gold and plant half of them in the ground but bring the other half back to the goddess. From each of those teeth, that he planted in soil, a fully grown and fully armed warrior sprang up immediately. Cadmus saw them as a threat and, therefore, made them fight each other by throwing few stones from opposite directions, making them think that the other warriors threw stones at them. After, when the bloody massacre had ended, only five warriors were left alive, declaring peace with each other. And these five warriors, also called "Spartoi" or "The Sown Men", pledged their allegiance to Cadmus and helped him build a city which he named Thebes, after the Egyptian Thebes, founded by his father.
He was about to live a happy life but the dragon monster, that he had slain in the process, was a son of god Ares and the god made him his servant for a period of eight years. After a long and dilligent eight-year servitude, Ares forgave him for what happened and granted him permission to marry with his daughter Harmonia. They had a beautiful wedding in the presence of all gods. It is said that even Europa, by now, a mother of Minos, Rhadamanthus and Sarpedon and a wife of Asterius of Deucalion's lineage, attended his wedding. And, on the top of everything, muses sang to their sacred marriage which was a rear treat for mortals. Later on, Cadmus and Harmonia had five children. Their names were Autonoe, Ino, Semele, Agave and Polydorus. His family members, however, had miserable lives, including sudden tragedies and unexpected misfortunes. Cadmus thought that he would suffer less, if he was a serpent. And the curse of the sacred dragon, that he had killed, transformed him into a serpent. Harmonia joined him as a serpent, after being granted her wish to share husband's fate. However, Zeus felt pity and was seeking justice. Therefore, he carried them to Elysian fields to continue their path in afterlife, in the company of the chosen mortals.