The Ilkhanid Heartland provides the first source on the fortified medieval (thirteenth and fourteenth centuries) settlement of Hasanlu Tepe in the western Azerbaigian province of Iran. Key problems addressed include the nature and dates of the fortifications, the difficulty of distinguishing Ilkhanid material from Saljuk, and land-use patterns in the Lake Urmia Basin and their relationship to the feudal system of land tenure and rural economic development...