After the tragic death of Raziuddin II, his son Shah Tahir Hussain Dakkani continued the tradition of the khanqah in Khwand, where the Sufis from Egypt, Bukhara, Samarkand and Qazwin flocked. It also influenced the local rulers and noblemen. The Safavid Shah Ismail became apprehensive of Shah Tahir's growing fame, therefore he invited him to join the Safavid scholars in his court at Sultaniyya. He joined the Safavid court in 926/1520 in the garb of the Twelver. It seems almost certain that it was a wise decision, and if Shah Tahir had not joined the court, Shah Ismail would have conducted a massacre of the Ismailis in Iran. According to "Ibrat-i Afza", "The widespread massacres of the Ismailis had been avoided due to the taqiya of Shah Tahir Hussain."
After some times, it seems that the rivals of Shah Tahir stirred up suspicions of Shah Ismail, so he left the court and moved to Kashan, where his followers once again thronged in large number. The local Shia ulema reported to Shah Ismail, accusing of leading the Ismailis and of corresponding with foreign rulers. Shah Ismail ordered his military commander to hasten to Kashan and eliminate Shah Tahir Hussain, but Mirza Shah Hussain Ispahani, a dignitary of the Safavid court, and an Ismaili, had informed Shah Tahir secretly of the king's intention. Shah Tahir left Kashan for Fars at once in Jamada I, 926/April, 1520. He fortunately boarded a ship sailing to India at Jardan, and reached Goa after eight days. When his ship anchored the port of Oman, he had an opportunity to convert Shah Qudratullah and his followers.
Shah Tahir went to Bijapur from Goa, where he was ignored by Ismail Adil Shah (915-941/1510-1534), the ruler of Bijapur. He left Bijapur for Gulbarga, and moved to Parenda. Khwaja Jahan, the governor of Parenda urged him to stay there for few more times. Thus, Shah Tahir resided at Parenda as a teacher and became famous for his learning. Meanwhile, Pir Muhammad Sherwani, the teacher of Burhan Nizam Shah (914-961/1508-1553) of Ahmadnagar, arrived in Parenda. He was so impressed by Shah Tahir's scholarship that he stayed there for one year, and learnt the system of astronomy and trigonometry. On his return to Ahmadnagar, Pir Muhammad Sherwani reported to Burhan Nizam Shah about Shah Tahir's knowledge. Finally, Shah Tahir was invited in Ahmadnagar, who reached there in 928/1522 and was feted a royal welcome. He rendered valuable services to the Nizam Shahi dynasty of Ahmadnagar in Deccan. Gradually, Shah Tahir became Burhan's principal counseller. His diplomatic and financial administrative duties however did not prevent him from dedicating himself to teaching, lectures and religious polemics. Shah Tahir did not disclose his Ismaili identity. Burhan Shah built a seminary for him in the fort, where Shah Tahir delivered lectures twice a week, and all the ulema and Burhan Shah himself attended.
In 944/1537, Burhan's son Abdul Qadir fell seriously ill. The Muslim and Hindu physicians failed in their treatment, but was healed at length by Shah Tahir. This event marked deep impression and regard in the heart of Burhan Shah, who embraced Ismailism under the garb of Twelvers. Sayyid Ahmadullah Qadri writes in "Memoirs of Chand Bibi" (Deccan, 1938, p. 102) that, "In 928/1522 when Shah Tahir, passing through Bijapur and Parenda, came to Ahmadnagar, Burhan Nizam Shah I, adopted the Ismailia religion in 944/1537. With the exception of Ismail Nizam Shah, who became Mahdi for a short time, all the rulers were Ismaili Shiahs." Burhan Shah also proclaimed Shiism as a state religion in Ahmadnagar. Pir Muhammad Sherwani and other Sunni ulema became jealous towards the religious success of Shah Tahir, who agitated against the proclamation. They were however arrested, but Shah Tahir spared the life of Pir Muhammad Sherwani for his past services, and was imprisoned. Pir Muhammad had been released after four years at Shah Tahir's appeal and his former office was restored to him.
Sayed Ali Tabatabai writes in "Burhan'i Ma'asir" (Hyderabad, 1936, p. 260) that Shah Tahir had adopted taqiya and did never tell of his real faith. Sayed Zakir Hussain also writes in "Tarikh-i Islam" (Delhi, 1918, 1st vol., p. 386) that Shah Tahir came from Iran and converted Burhan Shah to Shiism, and adopted taqiya in the court.
In 950/1543, Burhan Nizam Shah sent Khurshah bin Qubad al-Hussaini, a close relative to Shah Tahir as an ambassador in Iran at the court of Shah Tahmasp, who received him at Qazwin. Shah Tahmasp sent a letter to Shah Tahir in appreciation with many gifts for the endorsement of Shiism in Nizam Shahi state in Ahmadnagar. In return, Shah Tahir's son Shah Hyder was also sent from Ahmadnagar to Iran on a goodwill mission; who was yet in Iran when Shah Tahir died in Ahmadnagar in 956/1549 during the time of Imam Nuruddin Ali (d. 957/1550).
Shah Tahir had four sons and three daughters, in which Shah Hyder was an elder being born in Iran, and rest in India, namely Shah Rafiuddin, Shah Abul Hasan and Shah Abu Talib. Shah Tahir's brother Shah Jafar was also persecuted violently by the Safavids in Iran, who also came in India and attached with the administration of the state. The mission in guise of Shah Tahir had been continued by his successors, viz. Hyder bin Shah Tahir (d. 994/1586), Sadruddin Muhammad bin Hyder (d. 1032/1622), Muinuddin bin Sadruddin (d. 1054/1644), Atiyyatullah bin Muinuddin (d. 1074/1663), Aziz Shah bin Atiyyatullah (d. 1103/1691), Muinuddin II bin Aziz Shah (d. 1127/1715), Amir Muhammad bin Muinuddin II (d. 1178/1764), Hyder II bin Muhammad al-Mutahhar (d. 1201/1786) and Amir Muhammad bin Hyder al-Bakir, whose biography is not known. The modern writers of Momin-Shahis however makes Amir Muhammad bin Hyder al-Bakir as their last fortieth Imam in the line of Momin Shah (d. 738/1337). It is learnt that the Syrian Momin-Shahis, after sending in vain in India to locate the descendants of Amir Muhammad bin Hyder in 1304/1887, the bulk of them transferred their allegiance to the Imam of Kassim-Shahi line.
It should be remembered that being a learned Ismaili preacher, Shah Tahir's method differed starkly with the usual dawa system. If he was a Twelver, he certainly needed nothing to leave Iran, where he had good opportunity at the Safavid court. Farhad Daftary writes in "The Ismailis: their History and Doctrines" (London, 1990, p. 489) that, "One must bear in mind, however, that Shah Tahir and other Nizari leaders of the period were obliged to observe taqiya very strictly. It is certain that Shah Tahir propagated his form of Nizari Ismailism in the guise of Twelver Shiism, which was more acceptable to the Muslim rulers of India who were interested in cultivating friendly relations with the Twelve Shi'i Safawid dynasty of Persia."
Imam Abuzar Ali is said to have returned to Anjudan in 912/1507 after getting congenial atmosphere. He maintained his cordial ties with the local amirs, elites and the Safavids. Abuzar Ali is said to have betrothed to Sabira Khatoon, the daughter of Shah Ismail, and was granted the title of Amir al-Umra (chief of the chiefs). This matrimonial relationship suggests a close tie of the Imam with the ruling power in the mantle of the Twelver.
Imam Abuzar Ali died in 915/1509 and was buried in Anjudan. The Russain scholar W.Ivanow had visited Anjudan in 1937 to collect the details from the inscriptions of then existing graves and mausoleums of the Ismaili Imams. He failed to locate the grave of Abuzar Ali in Anjudan. But, before him, Muhammad Taqi bin Ali Reza, who compiled "Athar-i Muhammadi" in 1893 had visited Anjudan before the migratiion of Imam Aga Hasan Ali Shah in 1842. He had discovered the grave of Abuzar Ali, and writes, "Imam Abuzar Ali had been invested the honorific title of Amir al-Umra, whose description is still preserved on the marble slab of Imam's grave" (pp. 65-66). It tenaciously corroborates to the fact that the grave of the Imam in Anjudan had been decayed before the visit of W.Ivanow, and it is, of course, possible that the same would have been happened with the grave of Imam Murad Mirza.