Enayatollah Reza ( Persian : عنایت‌الله رضا ; June 18, 1920 in Rasht – July 20, 2010 in Tehran ) was an Iranian historian and professor of philosophy, a former member of the Iranian Communist Party , and a former Iranian military officer. He was a member of the Supreme Academic Council of the Centre for Iranian and Islamic Studies in Tehran , Iran , the publishers of the Encyclopaedia Islamica . His research concerned the historical regions of Iranian Azerbaijan and Caucasian Arran ; based on this research, he claimed that "Azerbaijan" should properly refer only to the land south of the Aras River (in Iran) and that the country of Azerbaijan should instead be called "Aran".