The Defterdar Mosque (or Nefterdar) is situated in Eleftherias’ square. The Financial Minister (Defterdar) of the Ottoman Empire Ibrahim Efendi built it at the end of the 18th century. It is a two-storey edifice of the same style and probably of the same time as the Lozia Mosque. The Koan historian Zarraftis, on the contrary maintains that the mosque was an earlier establishment that preceded the arrival of the Ottomans on the island, confirming the tradition that it was a Christian church dedicated to Saint Paraskevi.
A dome, supported by 12 arches, rises in the middle of the mosque. Two staircases, located on the eastern and western side, lead to the narthex. The eastern staircase, intended for the officials, has a vaulted cover. The interior of the mosque proper is adorned by 8 columns, while circular frames of inscriptions from the Koran constitute the only decorations on the walls. There are shops on the ground floor of the mosque and the minaret stands on its western side. A little further down, there is an octagonal marble fountain, covered by a dome supported by 6 arches, resting on an equal number of small pillars.
The Defterdar Mosque sustained extensive damage from the 2017 earthquake.
(Source: V. Hatzivasileiou, History of the island of Kos)