I first saw the minaret of this mosque before a restoration. Then I saw the restoration about to be finished. In 2018 I visited again, and was pleasantly surprised to find the mosque as well as the ablutions area had been adorned with fine quality tiles.

From the Wikipedia: "Eşrefoğlu Abdullah Rûmî (-1469) was a Turkish poet and mystic of the early years of Ottoman Empire. His original name was Abdullah, but he was known as Eşrefoğlu Rumi. He was born in İznik, and died there in 1469. His father Sayyid Ahmed came from Egypt and settled in İznik. After a theological education, Rumi turned to Sufism under the guidance of Haji Bayram Veli. Later, he founded the Eshrefiye branch of the Kadiri dervishes.
Rumi wrote in Turkish. While he is known for his Divan and Muzakki-l-nufus, he wrote many books such as Tarîkatnâme, Fütüvvetnâme, Delâil ün nübüvve, İbretnâme, Mâziretnâme, Hayretnâme, Elestnâme, Nasîhatnâme, Esrarüttâlibîn, Münâcaatnâme and Tâcnâme."