The Parsis, originally from Iran, migrated to India about 900 years ago. This they did to save their religion, Zoroastrianism, from invading Arabs who proselytized Islam. However, in 1689-90, when a severe plague had struck down most of the Europeans, the Siddi Chief of Janjira made several attempts to re-possess the islands by force, but the son of the former, a trader named Rustomji Dorabji Patel (1667-1763), successfully warded off the attacks on behalf of the British with the help of the 'Kolis', the original fisher-folk
inhabitants of these islands. The remnants of the Koli settlements can still be seen at Backbay reclamation, Mahim, Bandra, Khar, Bassien and Madh island.
The Zoroastrian Towers of Silence on Malabar hill were built by Seth Modi Hirji Vachha in 1672.The first fire-temple was also built in the same year by Seth Vachha opposite his residence at Modikhana within the British fort. Both of the these structures can still be seen today although they have been expanded and strengthened.