Abusaeid Abolkheyr (Persian: ابوسعید ابوالخیر) (December 7,967 - January 12 , 1049 / Muharram ul Haram,1 ,357 - Sha'aban,4 ,440 AH), also known as Sheikh Abusaeid or Abu Sa'eed, was a famous Persian Sufi who contributed extensively to the evolution of Sufi tradition.