The structure, erected from 1302 to 1312 CE, was claimed to be the oldest double-shell dome in Iran. This erroneous view of the construction was made by Dieulafoy but is totally disputed by Andre Godard. In Godard's view it is a normal, if spectacularly large dome, with a thin skin on top for the faïence and is in no way a double dome. Its importance in the Muslim world may be compared to that of Brunelleschi's cupola for Christian architecture. It is one of the largest brick domes in the world, just at the theoretical engineering limit for a brick dome and the third largest dome in the world after the domes of Florence Cathedral and Hagia Sophia.