Abu Ya'qub al-Sijistani

Abu Ya'qub Ishaq ibn Ahmad al-Sijistani or al-Sijzi (السجزي), also known as Bandaneh, was a 10th-century Persian Ismaili missionary active in the northern and eastern Iranian lands. His life is obscure, but he was a prolific writer, who played a crucial role in the infusion of Neoplatonic ideas into Isma'ili theology.