Muhammad al-Muzahhib (the illuminator) is a calligrapher who wrote both small and large nasta'liq. A copy of the Subhat al-Abrar of Jami, dated AH 951 (1544-45 AD) was also copied by him in Mecca (Mehdi Bayani, Ahval va Asar-e Khosh-Nevisan, Vol. III, Tehran, 1348, p. 894). He must therefore have worked in Herat, moved to Bukhara and travelled twice to Mecca in the years AH 1544-45 and 1561-62.
A manuscript with miniatures signed by Mahmud Muzahhib is lot 175 in the present sale. Please see that lot for a further discussion on him.