On the other hand, many Azeri words (about 1,200) entered Persian (still more in Kurdish), since Iran was governed mostly by Azeri-speaking rulers and soldiers since the 16th century (Doerfer, 1963–75); these loanwords refer Əsasly to administration, titles, and conduct of war. This long-lasting Iranian-Azeri symbiosis must be borne in mind if one is to understand the modern history of Iran and its language correctly.