Heraclius arrives by ship from Africa at 
Constantinople, overthrows 
East Roman EmperorPhocas and becomes Emperor. His first major act is to change the official language of the 
East Roman Empire from 
Latin to 
Greek (already the language of the vast majority of the population).  Because of this, after AD 610 the 
East Roman Empire is customarily referred to as the 
Byzantine Empire (the term Byzantine is a modern term invented by historians in the 18th century the people of the Empire itself always referred to themselves as Ρωμιούς – in English, Romious).