In 813/1410, Sayed Radi Kiya (798-829/1395-1426), the son of Sayed Ali, and a powerful ruler of Lahijan, had expelled the Hazaraspid and Kushayji amirs from Daylam. He also stroke a severe blow to the local Ismailis during his operations, and killed a few of the descendants of Imam Alauddin Muhammad.
Jalali bin Najmuddin of Qain writes in "Nassih al-Muluk" that, "In the period of my grandfather, Amadid-din in the first part of the 14th century, Kohistan, Rudhbar etc. were thickly inhabitated by the Ismailis, resulting the Sunni preachers to face difficulties to convert them." Jalali further writes that in his own period, in early 15th century, the bulk of the population was the Sunnis, though he had been assured that there were many Ismailis near Kohistan. It seems that Kohistan was populated by the Ismailis before Taymur's arrival in 794/1392, impelling them to move elsewhere during the time of Jalali from Kohistan and Rudhbar. According to "Siyasat al-Muluk" that the officers of Kohistan were more or less suspected by Shah Rukh (1405-1407). "The Encyclopaedia of Islam" (1927, 2nd vol., p. 550) also asserts that few soldiers, Sayeds or darwish of Qain in the time of Shah Rukh were suspected being the Ismailis.
It must be remembered that the Mongols had demolished some 70 castles of the Ismailis in the province of Kohistan, and after that, Turshiz a city of Kohistan recovered its importance, though partly in decay probably during this period where the Ismailis lived in the ruins of four castles in Turshiz, namely, Kalah Bardarud, Kalah Mikal, Mujahidabad and Atisgah. These castles finally had been demolished by Taymurlame in 783/1381, and since then, Turshiz disappeared from the map.
Kamaluddin Abdur Razzak (1413-1482), the son of Jalaluddin Ishaq Samarkandi had visited Kirman on May 21, 1441. He compiled "Matla'us Sa'dain wa Majmu'ul Bahrain"in 874/1470, but makes no mention of the Ismailis. Islam Shah lived in Kahek in obscure, and did not attract the historians to make his mention. Sayed Imam Shah (d. 926/1520), who had been in Kahek in the province of Kirman in 854/1450 writes in "Motto Das Avatar" (verse no. 10:141) that, "Imam Islam Shah resides in Kahek, but the ruler and people do not know him." Nuruddin bin Lutafullah (d. 834/1430) compiled "Tarikh-i Hafiz Abru" in 829/1425, however gave but a trivial account of the Ismailis during the time of Islam Shah in Iran.
The Syrian Ismailis lived in peace during the period under review in Hims, Aleppo, Hammah, Masiyaf, Qadmus etc., and had generated a close contact with Islam Shah through the local dais. Muhammad bin Sa'd bin Daud (790-859/1378-1455), surnamed ar- Rafnah was a gifted dai in Syria. He is reported to have visited Kahek few months before the death of Islam Shah in 827/1423. He also attended the ascension ceremony of Imam Muhammad bin Islam Shah. He was a prolific writer and wrote "Rasail al- Shifa", refuting the claims of the Momin-shahis. He also wrote "Khams Rasail Ismailiyya". Nuruddin Ahmad (d. 849/1445) was another dai of high fame in Syria, who had travelled widely in Syria, Iraq and Arabia. His "Fusul wa-Akhbar" deals the history of the Ismailis in Syria. Abul Ma'ali Hatim bin Imran, eminently known as Ibn Zahra also flourished in the period under review, who compiled "al-Ahkam wa'l Fatarat" and "al-Mabda wa'l Ma'ad".
The Ismailis of upper Oxus seems to have been unknown about the reduction of Alamut until the time of Islam Shah due to residing at farthest region. Their communication with the Iranian Ismaili Imams collapsed for over 150 years during the operations of Halagu and Taymur. Shagnan, the district of upper Oxus was the chief Ismaili centre in Central Asia. The early Arab geographers refer to Shagnan by the name, Shikinan and Shikina, while the Chinese writers call it She-ki-ni i.e., "the kingdom of the five She-ni" (gorges). Sayed Malang Shah is reported to have come here from Alamut, and converted a large number of the local inhabitants. He solidified his power and extended his influence and won over Farhad Rew, the chief of Shagnan. Sayed Malang Shah was followed by a young dai Sayed Khamush Shah Shirazi. Sir Thomas Douglas Forsyth (1827-1886) in "Report on a Mission to Yarkand, Calcutta, 1875",puts his date at 665/1266. Sayed Khamush Shah lived longer, and converted the Mongol tribes in upper Oxus. His tomb is at Kal'ai Barpanj. His descendants ruled Shagnan as hereditary Mirs during the time of Islam Shah, who penetrated the Ismaili dawafor the first time in China, including Yarkand and Pamir. It is a striking feature that the Ismailis of upper Oxus maintained that Islam Shah resided in India. Most of the Imam's dais followed route of Shagnan through Indian territory, and it is possible that they had constructed an idea that the Imam's residence was in India.