Hasan bin Sabbah
Hasan bin Sabbah (1034-1124) took possession of the fort of Alamut in Iran in 1090. His immediate concerns were to refortify Alamut, provide for it food and water supply, irrigate the field in the valley, acquire adjacent castles, erect forts at strategic points, institute economic and social reforms and unite the Ismailis by bonds of fraternity. Thus, he succeeded to establish the Nizarid Ismailis rule in Alamut. It appears from the fragments of the historical sources that, the Ismailis continued green colour as their standard, and Hasan bin Sabbah is reported to have hoisted it for the first time on the summit of the Alamut.