Zalmoxis (Greek: Ζάλμοξις) is a divinity of the Getae and Dacians (a people of the lower Danube), mentioned by Herodotus in his Histories IV, 93–96.
In later interpretations, which began with Jordanes (6th century AD) and proliferated during the 19th and 20th century, mainly in Romania (where it is known by the name of Zamolxis). Zalmoxis was regarded as the sole god of the Getae or as a legendary social and religious reformer who, according to Herodotus, taught the Getae a belief in immortality, so that they considered dying merely as going to Zalmoxis. Herodotus states that Zalmoxis was also called by some of the Getae Gebeleizis, which led some researchers to conclude that Getae were actually henotheists or even polytheists. Another discussion exists about the chthonic (infernal) or uranian (heavenly) character of Zalmoxis.
Herodotus writes about Zalmoxis in book 4 of his Histories:
93. ...the Getae are the bravest of the Thracians and the most just. 94. They believe they are immortal forever living in the following sense: they think they do not die and that the one who dies joins Zalmoxis, a divine being; some call this same divine being Gebeleizis. Every four years, they send a messenger to Zalmoxis, who is chosen by chance. They ask him to tell Zalmoxis what they want on that occasion. The mission is performed in the following way: men standing there for that purpose hold three spears; other people take the one who is sent to Zalmoxis by his hands and feet and fling him in the air on the spears. If he dies pierced, they think that the divinity is going to help them; if he does not die, it is he who is accused and they declare that he is a bad person. And, after he has been charged, they send another one. The messenger is told the requests while he is still alive. The same Thracians, on other occasions, when he thunders and lightens, shoot with arrows up in the air against the sky and menace the divinity because they think there is no god other than their own.
Herodotus asserts that Zalmoxis was originally a human being, a slave who converted the Thracians to his beliefs. The Greeks of the Hellespont and the Black Sea tell that Zalmoxis was a slave of Pythagoras, son of Mnesarchos, on the island of Samos. After being liberated, he gathered huge wealth and, once rich, went back to his homeland. Thracians lived simple hard lives. Zalmoxis had lived among the wisest of Greeks, such as Pythagoras, and had been initiated into Ionian life and the Eleusinian Mysteries. He built a banquet hall, and received the chiefs and his fellow countrymen at a banquet. He taught that neither his guests nor their descendants would ever die, but instead would go to a place where they would live forever in a complete happiness. He then dug an underground residence. When it was finished, he disappeared from Thrace, living for three years in his underground residence. The Thracians missed him and wept fearing him dead. The fourth year, he came back among them and thus they believed what Zalmoxis had told them.