some historians, Iranians, in fact, fought long and hard against the invading Arabs." By 651, most of the urban centers in Iranian lands, with the notable exception of the Caspian provinces and Transoxiana, had come under the domination of the Arab armies. Many localities in Iran staged a defense against the invaders, but in the end none was able to repulse the invasion. Even after the Arabs had subdued the country, many cities rose in rebellion, killing the Arab governor or attacking their garrisons, but reinforcements from the caliphs succeeded in putting down all these rebellions and imposing the rule of Islam. The violent subjugation of Bukhara after many uprisings is a case in point. Conversion to Islam was, however, only gradual. In the process, many acts of violence took place, Zoroastrian scriptures were burnt and many mobads executed. Once conquered politically, the Persians began to reassert themselves by maintaining Persian language and culture. Regardless, Islam was adopted by many, for political, socio-cultural or spiritual reasons, or simply by persuasion, and became the dominant religion. Mongol rule The Mongol invasion of Iran resulted in millions of deaths and ruined many cities. The early Mongol invaders were, however, pagans or Buddhists so their persecution was not as targeted against Zoroastrians as before. However, within half a century of the conquest, the leader of the Il-Khanate, Ghazan Khan, converted to Islam, which did not help the status of Zoroastrians in Iran. However, by the time that the Mongols were expelled, Pars province had escaped major damage and the Zoroastrians moved to the North of Pars mainly in the regions of Yazd and Kerman, where even today the main Zoroastrian communities are found. Modern history Safavid dynasty The Shiite Safavid dynasty destroyed what was once a vibrant community of Zoroastrians. As per official policy, Safavids wanted everyone to convert to the Shia sect of Islam and killed hundreds of thousands of Zoroastrians and other minorities when they refused. The majority of Zoroastrians also left for India though about 20% remained, most of whom had to migrate in the late 19th century as the Qajar dynasty imposed greater restrictions on them. Qajar dynasty During the Qajar dynasty, religious persecution of Zoroastrians was rampant. Due to the increasing contacts with influential Parsi philanthropists such as Maneckji Limji Hataria, many Zoroastrians left Iran for India. There, they formed the second major Indian Zoroastrian community known as