Imperial Greek, simply known as Greek, is a Hellenic language and the sole official language of the magical Roman Empire. It is an evolution of Medieval Greek, which split into two variations, the other one being known as Modern Greek and solely used in the muggle world. It originates in the dialect used by the artists of the Roman Renaissance in their works, being a much heavier mixture of Greek and Latin than before, with many Latin words becoming hellenized. Eventually, this version of Medieval Greek spread out amongst the populace, and later, in order to differentiate from the Greek spoken by the muggles, this dialect was officially elevated into a new language and was named as Imperial Greek.
King of Kings, Ruling Over Rulers (first appearance)