Salman al-Farsi

Originally named Ruzbeh, he was born in Persia into a Zoroastrian priest's family. Unsatisfied with fire worship, he investigated Christianity and fled home, traveling to Syria to study under scholars. His last Christian teacher, on his deathbed, foretold the arrival of a final Prophet in Arabia who would accept gifts but not charity, and bear the Seal of Prophethood on his back.

Ruzbeh traveled to Arabia, was betrayed by caravan guides, sold into slavery, and ended up in Madinah. When the Prophet migrated to Madinah, Ruzbeh tested him with these three signs, verified them, and became Muslim. The Prophet helped him buy his freedom.

During the coalition siege of Madinah (627 CE), Salman proposed digging a massive trench (Khandaq), a Persian defense tactic unknown to Arabs. This genius strategy saved Madinah. In later years, he served as governor of Al-Mada'in in Iraq, living in extreme simplicity.