The earliest documents where the fort of Bihach is mentioned dates from 1260. During the mediaeval period, it developed as a free royal town with not only the fort but two monasteries, several churches, many commercial buildings and houses, and a number of defense towers.
Later on, one of the medieval churches in Bihach dedicated to St. Anthony was transformed into a mosque in 1592. It was given the name Fethija. The name comes from the word fath which means victory. At that time the gothic bell tower of the building was used as a minaret. But the minaret you will find there today was erected around 1863. When visiting the mosque do not forget to take a look to the small harem close to it.
There used to be nine tombstones from the former church laid face upwards in the floor of the mosque. Today you can enjoy them in the National Museum in Sarajevo.