A tughra is a calligraphic seal or signature of an Ottoman sultan that was affixed to all official documents and correspondence. It was also carved on his seal and stamped on the coins minted during his reign.
The tughra was designed at the beginning of the sultan's reign and drawn by the court calligrapher on written documents. The first tughra belonged to Orhan I (1284-1359), the second ruler of the Ottoman Empire and it evolved until it reached the classical form in the tughra of Sultan Suleiman the Magnificent (1494-1596).
Tughras served a purpose similar to the cartouche in ancient Egypt or the Royal Cypher of British monarchs. Every Ottoman sultan had his own individual tughra. The picture of embroidery dated 1912 above shows tughra of Sultan Mehmed Reşad V, embroided with golden thread.