7th to 9th century.
First Croatian “official” language was Latin and Croatian name is recorded in Latin inscriptions of Croatian rulers (dukes and kings) in the 9th century.
The earliest Croatian Dukes and Kings
THE MUSEUM OF CROATIAN ARCHEOLOGICAL MONUMENTS
The dominance of Church Slavonic, first literary language of all Slavs, based on a south Macedonian dialect. In time, variants of Church Slavonic emerge (Croatian, Russian, Czech, Serbian, Bulgarian), as a result of intrusion of the vernacular. First Croatian script, Glagolitic, was probably invented by missionaries from Thessalonica Cyril and Methodius (ca. 850), whose disciples, expelled from Moravia (contemporary Slovakia and Czech Republic), settled in Croatian lands. The originally “round” form of Glagolitic script soon becomes angular- the distinct feature of Croatian Glagolitic. Historicallly, the most important monument of early Croatian literacy is the Baška tablet (ca. 1100).
THE BASKA TABLET
precious stone of Croatian literacy
Croatian Glagolitic Script
Old Church Slavonic Institute