From the New Anatolian:

Galleries, negropols, passageways and granaries, dating back to Roman and Byzantine periods, were unearthed during the excavations carried out in Han Underground City of central Anatolian city of Eskisehir," said Ahmet Oguz Alp from Anadolu University's Department of Art History.

"Although it is not clear yet, we think that the city might have been used as a military base in the past. People might have used the city as a place of shelter or to wage attacks in order to protect themselves from Arab and Turkish incursions as well," Alp affirmed.

Alp also noted that the city had a great importance, as it was used as a military route before the Ottoman Empire and a route for pilgrimage afterwards.

The excavation work at the historical site will end on August 22nd.

Eskisehir is what we would call Dorylaeum/Dorylaion although I don't recall anything 'ancient' of note happening there (there was a big battle during the Crusades there)