India, Feb. 13 -- The death of Karim Al-Hussaini Aga Khan IV, the 49th Imam of Ismaili Muslims, known for his philanthropic work and heritage conservation projects in India, is an occasion to revisit the fascinating history of the Nizari Ismailis, the Khojas and how the first Aga Khan came to be recognised by the British as a ruler in India.

The Aga Khan, a hereditary position, is the head of the Nizari Ismaili sect, the largest branch of the Ismaili sect. Both are Shia sects that trace their origins back to the time of Prophet Mohammad and the succession crisis that followed his passing in the 7th century.

The Ismailis acquired political power through the formation of the Fatimid Caliphate in the 10th century and conquered large areas ...