The maritime part of Dalmatia continued to be called Roman Dalmatia, and remained subject, to the Byzantine Empire. Dubrovnik, however, governed itself as an aristocratic republic. Manuel Comnenus in 1170 gave to the city the rights of citizens of Constantinople. The Latin language, although modified (Dalmatian language), continued to be spoken in Dubrovnik till the 13th century, when it was gradually superseded by the Slavs. The senate however decreed that the Latin should continue to be the language of administration, and in order to keep on the study of it, they created and instituted a chair of Latin. There it is described in separate chapters, its form of government, its church (attached to the Latin communion), its laws, customs, its relations with the Republic of Venice and with the Slavic principalities of Croatia and Bosnia, its policy towards the Ottomans and its commerce.