Iran has always been a gathering of different ethnic groups. From 1501 to 1524 Shah Ismail(I) ,who was a man from Azeri ethnic group from north west of Iran ,united all of Persia under Iranian leadership after some nine centuries of foreign or fragmented rule. Being a Shiite, he declared Shi"ism as the state religion and converted virtually all of Persia and some surrounding areas under his control from Sunnis to Shi"ism. Shi"ism became a medium for the Persians to differentiate themselves from the rest of the Islamic world, in particular from the Sunni Ottomans. To ensure its continuation as the state religion, the Safavid kings who were basically Azeri supported the Shiite clergy. Shah Ismail(I) is known as the first person who declared Iranian "nation" in the history of Iran. He was Azeri and from his time Azeris started to speared all through the country. Now Iran has 30 million populations who live in the provinces that they are known as Azeri provinces. Azeris form 24% of Iran"s population According to CIA fact book.
Azeris has been a very powerful group in Iran. They are the symbol of resistance in front of foreign attacks. during the World War, The Soviet Union mounted a full-scale invasion of northern Iran in 1941, and after 1945 its refusal to withdraw from the Iranian part of Azerbaijan was one of the cold war"s opening gambits. Iran lost some important cities in Azerbaijan during Torkamanchay and Golestan conventions. Russia"s army was in Tabriz and famine had killed lots of people. Some of the analysts say that Iran"s modernization had started from that historical defeat; when people saw that despite all their courage, the technology gives more power to Russians.