Mohammad-Reza Shajarian (Persian: محمدرضا شجريان) (born 23 September 1940 in Mashhad, Iran) is an internationally and critically acclaimed Persian traditional singer, composer and ostad (master) of Persian music. He has been called "Iran's greatest living master of traditional Persian music."Shajarian is also known for his skills in Persian calligraphy, and humanitarian activities. Shajarian started singing at the age of five, under the supervision of his father, and at the age of twelve, he began studying the traditional classical repertoire known as the Radif. Shajarian started his singing career in 1959 at Radio Khorasan, rising to prominence in the 1960s with his distinct style of singing. His main teachers were Ahmad Ebadi, Esmaeil Mehrtash, Abdollah Davami, and Nour-Ali Boroumand. He also learned the vocal styles of singers from previous generations, including Reza Gholi Mirza Zelli, Fariborz Manouchehri, Ghamar Molouk Vaziri, Eghbal Azar, and Taj Isfahani. When giving a lecture at California State University, Sacramento on March 2, 2012, he was asked what teacher was most influential to his development, and he cited legendary Iranian tar musician Jalil Shahnaz, indicating that Shahnaz' playing style was what he most tried to mimic with his own singing style. Shajarian has collaborated with Parviz Meshkatian, Mohammad Reza Lotfi, Hossein Alizadeh, and Faramarz Payvar. He is recognised as skilled singer in the challenging traditional Dastgah style. In 1999 UNESCO in France presented him with the Picasso Award and in 2006 with the UNESCO Mozart Medal.