and the beliefs that it represented. At the same time no strict rules were applied to govern this form of Islamic architecture. The great mosques of Khorasan, Isfahan and Tabriz each used local geometry, local materials and local building methods to express, each in their own way, the order, harmony, and unity of Islamic architecture. When the major monuments of Islamic Persian architecture are examined, they reveal complex geometrical relationships, a studied hierarchy of form and ornament and great depths of symbolic meaning. In the words of Arthur U. Pope, who carried out extensive studies in ancient Persian and Islamic buildings: However, Pope's approach toward Qajar art and architecture is quite negative. Persian domes The Sassanid Empire initiated the construction of the first large-scale domes in Persia (Iran), with such royal buildings as the Palace of Ardashir and Dezh Dokhtar. After the Muslim conquest of the Sassanid Empire, the Persian architectural style became a major influence on Islamic societies and the dome also became a feature of Muslim architecture (see gonbad). The Il-Khanate period provided several innovations to dome-building that eventually enabled the Persians to construct much taller structures. These changes later paved the way for Safavid architecture. The pinnacle of Il-Khanate architecture was reached with the construction of the Soltaniyeh Dome (1302–1312) in Zanjan, Iran, which measures 50 m in height and 25 m in diameter, making it the 3rd largest and the tallest masonry dome ever erected. The thin, double-shelled dome was reinforced by arches between the layers. The renaissance in Persian mosque and dome building came during the Safavid dynasty, when Shah Abbas, in 1598, initiated the reconstruction of Isfahan, with the Naqsh-e Jahan Square as the centerpiece of his new capital. Architecturally they borrowed heavily from Il-Khanate designs, but artistically they elevated the designs to a new level. The distinct feature of Persian domes, which separates them from those domes created in the Christian world or the Ottoman and Mughal empires, was the use of colourful tiles, with which the exterior of domes are covered much like the interior. These domes soon numbered dozens in Isfahan and the distinct blue shape would dominate the skyline of the city. Reflecting the light of the sun, these domes appeared like glittering turquoise gems and could be seen from miles away by travelers following the Silk road through Persia. This very distinct style of architecture was inherited from the