Shah Tahir, also known as Tahir Shah, (Arabic: شاه طاهر الحسيني الدكني, romanized: Shāh Tāhir al-Husayni al-Dakkani; 1486 – 1549) and known in his lifetime by his followers as Hujjatullah was a Nizari Ismaili Imam from the Muhammad-Shahi (Mu'mini) line and an astronomer and philosopher who served as a minister of the Nizam Shahi dynasty in South India.
Imam Shah Tahir was born in Khund, a village in Gilan near the border with Qazvin, that has since been abandoned.
He left Bijapur and moved to Parenda, where he started teaching almagest, a treatise by Ptolemy on astronomy.
Eventually, in 1538 AD, he persuaded the Sunni sultan to convert to Nizari Shi'ism, of which he was imam of the largest branch at that time.
[4][5][6] He wrote many books, among them were:[7] He died in 1549 AD and his body was sent to Karbala to be buried near the tomb of Husayn ibn Ali.