Zalmoxis

Zalmoxis (Greek Ζάλμοξις, also known as Salmoxis, Σάλμοξις, Zamolxis, Ζάμολξις, or Samolxis Σάμολξις) was a legendary social and religious reformer, regarded as the only true god by the Thracian Dacians (also known in the Greek records as Getae Γέται). According to Herodotus (IV. 95 sq.), the Getae, who believed in the immortality of the soul, looked upon death merely as going to Zalmoxis, as they knew the way to become immortals.
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[Greek] A god of the Getae and Dacians, a people of Thrace near the Hellespont. Assuming a human form, he lived among humans but disappeared into the underworld for three years and returned in the fourth. He was said to have brought mystic lore regarding the immortality of the soul from Egypt and from Pythagoras, introducing this concept, together with the arts of civilization, to his people. 

ZALMOXIS [O ZAMOLXIS, O ZALMOXE, O SALMOXIS, SEMI-LEGGENDARIO RIFORMATORE SOCIALE E RELIGIOSO]