Your large sized original early 20th century painting is done in the 19th century Orientalist style. Orientalist is the name for the art movement that primarily depicted people and lifestyles from the Middle East and Northern Africa. Sani al Soltan was the title name bestowed by Naser al-Din Shah to the Baha'i artist, Mirza Ataullah Khan Ata'i, who had converted to Islam. The estimate is based on recorded auction sales of comparables.