Ar - Rāzī, a ninth - century Persian considered by some to have been the greatest physician of the Islamic world of that time, wrote the first medically accurate description of smallpox.
नवव्या शतकातील अर - राझी या इराणी वैद्याला काहीजण त्या काळच्या इस्लामी जगातील सर्वात महान वैद्य मानतात.