The Second Zoroaster is a title that refers to a mysterious precursor and possible direct teacher of the Iranian prophet Mazdak, the eponymous founder of Mazdakism.
Born in Fasa in the Sasanian Empire, he founded a heterodox and syncretic sect of Zoroastrianism called Dorostdini. Dorostdini was the root of Mazdakism, and the sect put emphasis on the use of wisdom instead of religious laws. For many years he lived in the Byzantine Empire.
Mazdakism (Persian: مزدکیه, romanized: mazdakīye) was an Iranian religion, which was an offshoot of Zoroastrianism.
The religion was founded in the early Sasanian Empire by Zaradust-e Khuragen, a Zoroastrian mobad who was a contemporary of Mani (d. 274). However, it is named after its most prominent advocate, Mazdak, who was a powerful and controversial figure during the reign of Emperor Kavad I (r. 498–531), until he was killed by Emperor Khusrau I (r. 531–579).