Bulgaria has strong ties with both ancient Greece and Rome. Many of its coastal cities such as Varna, Nesebar, and Sozopol are the descendants of Greek colonies established during the period of Greek colonisation (8th to 6th c. BCE), leaving a rich archaeological patrimony in the country. As part of the Roman Empire’s Thracia and Moesia Inferior provinces, the lands of Bulgaria served as an important trade route, which gave prominence to cities such as Serdica (now the capital Sofia) and Philippopolis (now Plovdiv). During the Middle Ages, Bulgaria’s proximity to the Eastern Roman (Byzantine) Empire meant that it played an interesting role in shaping the Empire’s politics and it therefore appeared often in Greek historical sources from the time. What is more, Bulgaria’s Christianisation that took place in the second half of the 9th c. was as much the result of the direction of Constantinople’s foreign policy of expanding its cultural influence as it was the fruit of the political acumen of the then ruler – knyaz Boris I (r. 852–889).