The Ferhadija mosque was the central building of the Banja Luka town and one of the most successful achievements of Islamic architecture of the 16^th century. It was built in 1579, as is witnessed by an epitaph on a stone plaque mounted above the entrance, at the time when Ferhad Pasha was still the Bosnian Sanjak-beg. Having come from the position of Klis Sanjak-beg to Banja Luka in 1574, which had already become the centre of the Bosnian Sanjak, to the position of Sofi Mehmed Pasha, Ferhad Pasha did not continue with the building in the already densely populated and urbanised Old Banja Luka, Gornji Seher, but he decided for a more flat terrain, north of the old centre.  Staying true to Islamic tradition of using a vakuf system of constructing buildings and adhering to the principle that “everyone’s work is their best offspring” he, in the period between 1574 and 1587, built 215 buildings in Banja Luka. These were a mosque, a fountain with a water supply, a mekteb, a caravanserai and with it a grain barn, a tophane, a hammam, two bridges, mills on Vrbas, palace for the governor, 200 shops, several public toilets and coblestoned two roads “from mektebs to tophana”and “from old Banja Luka to the market place”. In order to ensure the duration of the new facilities for centuries, he determined the conditions of their use, maintenance and guarding of the endowment, written between 21^st and 30^th January 1587 which, in addition to the divan secretary Sebzija, the writer of this document, was signed by a large number of witnesses, distinguished and respected people in Banja Luka at the time. Already at that time, Banja Luka was the seat of the Bosnian eyalet, which was founded in 1580, whose first beglerbey was Ferhad Pasha. Ferhad Pasha Sokolovic was a member of the famous Sokolovic family that marked a part of history of Bosnia at the time when the Ottoman Empire was at the height of its power. The Sokolovic family comes from the village with the same name near Visegrad. The most powerful among them was Mehmed Pasha Sokolovic, Grand Vizier of three sultans, Suleiman I, Selim II and Murat III, who strongly helped his family members, often putting them to positions of governor of conquered areas. The same was with Ferhad Pasha who was named the vizier of Buda in 1588, but was killed in Buda in 1590.