Parsi tradition holds that soon after their settlement at Sanjan, the migrant Zoroastrian community consecrated a fire of the highest ritual grade, later known as the Iranshah, King of Iran, in recognition of the sovereignty and religious authority the community had left behind in its homeland. Consecrating and maintaining a fire of this grade required an elaborate ritual process, drawing embers gathered from multiple different types of fire including, by tradition, one produced by lightning, and once established, a fire of this rank was treated as requiring continuous, unbroken maintenance rather than being extinguished and relit.
The Iranshah fire did not remain in one location. Zoroastrian tradition and later community records describe it being moved several times over the centuries in response to periods of conflict, invasion and instability affecting western India, with each relocation requiring the fire's priests to transport the sacred flame under careful ritual protection to a new place of safety.
The fire's most recent and long lasting home has been at Udvada, on the Gujarat coast, since 1742 CE, where it has continued to burn without interruption since that date, making it, by Parsi tradition, one of the longest continuously maintained sacred fires in the Zoroastrian world and the single most important pilgrimage site for the Parsi community today.