Zağnos Pasha Mosque or Balıkesir Ulu Mosque was built in 1461 by Zağnos Pasha, one of the viziers of Fatih Sultan Mehmet, as a complex in Balıkesir. Today, its bath and mosque are standing. It is a complex with a mausoleum, muqakkithane and hammam around it.
The mosque was built in 48 weeks with the appointment of 6 men of Fatih and opened to worship with a great ceremony on March 3, 1461. The mosque was built in 1460-61 by Zağnos Pasha, son of Vrana Konti, the friend of Albanian Alexander. It was badly damaged in an earthquake in 1897. The mosque today was rebuilt in 1902. It is the largest mosque in Balıkesir with a capacity of 1000 people. It is located in the middle of Balıkesir. Mehmet Akif Ersoy gave a sermon in this mosque during the Turkish War of Independence and excited the public about saving the homeland. It is also the first and only mosque where Atatürk read his sermon. That sermon is known as Balıkesir Sermon. You can watch all parts of the city from the minaret of the mosque.
The mosque today was built in 1904 by Ömer Ali Bey, the governor of the period, on the foundations of the old mosque.