
1) Former city in Iran 2) Sasanian city 
Found on 
https://www.crosswordclues.com/clue/hulwan

 Hulwan was an ancient town on the Zagros Mountains in western Iran, located on the entrance of the Paytak Pass, nowadays identified with the village of Sarpol-e Zahab. == History == Later Arab tradition, as recorded by al-Tabari, considered the town a Sasanian foundation dating to Kavadh I (reigned 488–496, 498–531), but it is far more ancient...
Found on 
http://en.wikipedia.org/wiki/Hulwan
 [East Syrian Ecclesiastical Province]
[East Syrian Ecclesiastical Province]  Hulwan (Syriac: ܚܘܠܘܐܢ), one of the chief towns in the western Iranian province of Media, was a metropolitan province of the Church of the East between the eighth and twelfth centuries, with suffragan dioceses for Dinawar, Hamadan, Nihawand and al-Kuj (perhaps Karaj d`Abu Dulaf). Hulwan was ranked...
Found on 
http://en.wikipedia.org/wiki/Hulwan_(East_Syrian_Ecclesiastical_Province)
  No exact match found.