The history of the province of Ardabil is a part of the history of Azerbaijan. Most Iranian historians believe that the city was built by Firooz, the Sassanid king (457-489 AC), and the city has a 1500 year history. But even earlier, Ardabil was a very important city from the military and political points of view during the Achaemenid period, which was a military base on the northern border of the Persian Empire. according to Avesta, the Iranian profit, Zoroaster was born near the river ” Daei Yeat ” which is now named “Aras” , and he had written his book in Sabalan area, while he began to propagate his religion in the city of Ardabil.
At the time of the Muslim Arabs invasion of Iran, (year 22 AH) the city of Ardabil was the largest in Azerbaijan, which failed to the Muslims. Between 257-317 AH it was the headquarters of the local government of Bani Saj who changed their capital from Maragheh to Ardabil. And the city of Ardabil remained the capital of Azerbaijan until the Moguls attack.