Turkey founded the Ottoman Empire, a dominant force from the late 13th century until the early 20th. Its first stamps were issued in 1863. They pictured the tughra or monogram of Sultan Abdul-Aziz, the symbol of his sovereignty. The stamps also showed the crescent, which along with a star on later issues, was the symbol of the Turkish caliphate. Turkey was ahead of many western nations when it became one of the first countries to issue Postage Due stamps. A Turkish occupation stamp was the world’s first octagonal issue. And Turkey issued one of the largest commemorative stamp sets ever at 134 varieties.