Raised to a high art form within the Ottoman chancery, the tughra served as the official seal of the sultan. Affixed to every royal edict, this stylized signature is an intricate calligraphic composition comprising the name of the reigning sultan, his father’s name, his title, and the phrase “the eternally victorious.” Its bold, gestural line contrasts with the delicate swirling vine-scroll illumination used to ornament the seal.