The name Latin was in the Middle Ages a common demonym among the followers of the Latin Church of Western Christianity. It derived from the Ecclesiastical Latin that was developed by the Latin Church fathers in the Western Church. Although Latin language was the official language of the Roman Empire, going back to the Italic tribe who in antiquity developed in Ancient Rome, the name was used irrespective of ethnicity, including by Germanic, Italic, Celtic and Slavic peoples. Thus the people associated with the states created during the Crusades were generally referred to as Latins or Franks, the latter being one prominent group represented.
In the Byzantine Empire, and the broader Greek Orthodox world, it was generally a negative characterisation, especially after the East-West schism in 1054.