This is the Işak Paşa Mosque. It was built by Işak Paşa who commanded the Ottoman forces during the siege of Istanbul, during the reign of Murad II, Fatih the Conqueror and Bayezid II (He was the Grand Vizier of Fatih the Conqueror twice and once for Bayezid II). It is understood from the foundation records that the construction was before 873 H (1468-69). In terms of construction characteristics, it is considered as the continuation of the architecture school called the Bursa style. It is similar to the Hamza Bey Mosque in Bursa considering its plan.
We see the ablutions fountain to the left, the front of the mosque, and somewhat distant to the right the mausoleum.