This is the Murat Paşa Mosque, built during the reign of Sultan Selim. The very kind imam showed me around and then took me to his quarters, to the left of the entrance, that contained a Seljuk medrese, that was in need of restoration, if only because the outside wall was still pockmarked by Russian bullets from the 1918 struggle (or earlier when the Russians took it in 1916).
These are the bullet holes.