This is Darwish Pasha Mosque (Dervish Pasha Mosque, Derwish Pasha Mosque, Dirwish Pasha Mosque, Darwish Bacha Mosque, Darwiche Pasha Mosque, Dervis Pasa Camii) the It was erected in 1574 by the Ottoman governor of Damascus Darwish Pasha. The building is built with alternating courses of black and white stones and is composed of a prayer hall preceded by a portico and a rectangular courtyard.
The mosque courtyard is entered from the east through an arched doorway set inside a high portal along Darwish Street. Above the door is an Arabic inscription carved in marble stating the name of the mosque’s patron and its erection date. On each side of the portal arch are two medallions of polychrome stone. The cylindrical minaret, crowned by a conical roof above a single balcony supported on muqarnas corbels, rises directly above the portal and is accessed by a spiral staircase entered from the courtyard.

In a street to its left I found the entrance to a prayer hall, I am not certain this one is the same I would have entered if I'd found the courtyard open. I took some shots of that also.