 The common heritage of both nations played a significant role in the close relations between the two countries, ever since the Medieval Ages, between Southern Slavs and Byzantine Greeks (the Byzantine Empire played a prominent role in spreading of the Orthodox Christianity to Bulgaria and the rest of the Balkans).The missionaries Cyril and Methodius from the city of Thessalonica were the founders of the Glagolitic Alphabet and the first literary language of the Slavs, from which the modern Bulgarian Language evolved.In the late 14th century - early 15th century, both Bulgaria and Greece came under Ottoman rule for nearly five centuries.