Istanbul has always been an important center for the art of calligraphy, which involves adding aesthetic form to scripture. Calligraphy can be found in manuscripts, wall panels, on the inner sides of domes, on the minarets, tombstones, and on tiles. Works of calligraphy are made by calligraphers while the tughras (monograms of sultans) were made by tughrakeshes. Select examples of calligraphy can be viewed at museums or on architecture.