These measures and the increasing arbitrariness of the Shah’s rule provoked both religious leaders who feared losing their traditional authority and students and intellectuals seeking democratic reforms. These opponents criticized the Shah for violation of the constitution, which placed limits on royal power and provided for a representative government, and for subservience to the United States. The Shah saw himself as heir to the kings of ancient homeland, and in 1971 he held an extravagant celebration of 2,500 years of Persian monarchy. In 1976 he replaced the Islamic calendar with an “imperial” calendar, which began with the foundation of the Persian empire more than 25 centuries earlier. These actions were viewed as anti-Islamic and resulted in religious opposition.