The Orthodox Christian civilization began around AD 680 and survives today in Turkey and Eastern Europe. What?

The Orthodox Christian civilization began around AD 680 and survives today in Turkey and Eastern Europe. What alphabet was developed by these people?

Sometime during the 10th century AD a new alphabet appeared which was known as Cyrillic and named after St Cyril. It was possibly invented by St Kliment of Ohrid, a missionary in Bulgaria. The Cyrillic alphabet was used to write the Old Church Slavonic language and was later adapated to write many other languages.