The tzangion (Greek, Ancient (to 1453);: τζαγγίον, in Greek, Modern (1453-); pronounced as /tsaŋˈgion/), plural tzangia (Greek, Ancient (to 1453);: τζαγγία) was a type of boot or sandal, which in the Middle Ages became an important part of the Byzantine Emperors' regalia.
In the 4th century, the was a type of elegant shoe, but its use as an imperial vestment in Byzantium only began later, and was influenced by eastern, most likely, Persian, usage. Thus the first occurrence of the as a sign of royal power is in John Malalas' description of the coronation of Tzath I as king of Lazica under Justin I, where Tzath was dressed in Roman imperial garb, but wore, decorated with pearls "in the Persian manner", rather than the Roman emperor's . By the 9th century, the wearing of red had become firmly associated with the imperial office, so much so that rebels putting them on signified their usurpation of the imperial title. In the mid-14th century, Pseudo-Kodinos reports that the were tall boots decorated with eagles out of pearls and precious stones.
The term is the root for the Greek term for shoemaker, (Greek, Modern (1453-);: τσαγκάρης), via (Greek, Ancient (to 1453);: τζαγγάριος), although a maker of imperial was called (Greek, Ancient (to 1453);: τζαγγάς).