File:Inegöl İshak Paşa Külliyesi 1554.jpg

English: An elaborate calligraphy, using different scripts. Late-Ottoman, 19th century.

The main feature are four ‘vav’ (the 27th letter of the modern Arabic alphabet). They refer to the words ‘vakıf’ (pious foundation), ‘veraset’ (legacy), ‘velayet’ (custody) and ‘vasiyet’ (last will/Testament), which are all four related to the concept of the ‘Külliye’ (a complex of buildings, centered around a mosque and managed within a single pious institution).

Islamic calligraphy, also known as ‘Arabic calligraphy’, is the artistic practice of handwriting, calligraphy, and by extension, of bookmaking, in the lands sharing a common Islamic cultural heritage. This art form is based on the Arabic script, which for a long time was used by all Muslims in their respective languages. Ottoman Turkish calligraphy is associated with abstract arabesque motifs on the walls and ceilings of mosques as well as on the page. The calligrapher can pursue different goals: the pure beauty of the line, the readability of the text, the monumentality of the inscription, symmetry, dynamic flow, even the suggestion or contours of an object. Muslims used calligraphy to represent God because they denied representing God with images. It is especially revered among Islamic arts since it was the primary means for the preservation of the Koran. Suspicion of figurative art as idolatrous led to calligraphy and abstract depictions becoming a major form of artistic expression in Islamic cultures, especially and particularly in religious contexts.

Info from J.M.Criel, Antwerpen. Sources: Website of ‘bursaulucami.blogspot.be’ & Wikipedia .

The complex 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. It is part of a larger complex, that consisted of mosque, madrasa, tomb, imaret, inn and stables but most have not survived to the present day, and there is no information about their architecture. A madrasa to the north of the mosque consists of twelve rooms behind the porticos lined up in a "U" shape and a classroom overflowing on the axis. From the three-line Arabic inscription on the door of the classroom, it is understood that the building was completed in 887 (1482).

A tomb located in the southwest of the mosque was built for Tâcünnisâ Sultan Hatun, the wife of İshak Pasha, as understood from the endowment. Işak Paşa's own tomb was moved because it was in the way, it was unclear to me where it is.