Interior of the Dome at Shah Mosque, Isfahan, Iran
After the introduction of domes into then Islamic architectural designs by Arabs during the 7th century, domes appeared frequently in the architecture of mosques. The Persians had constructed such domes for centuries before, and some of the earliest known examples of large-scale domes in the World are found in Iran. So, the Safavid Muslims, who ruled from 1501 to 1722, borrowed heavily from pre-Islamic knowledge in dome-building, that is the use of squinches to create a transition from an octagonal structure, into a circular dome. To cover up these transition zones, the Persians built rich networks of stalactites. Thus, came also the introduction of this feature into Persian mosques.