The Holy Roman Empire emerged around 800, as Charlemagne, king of the Franks, was crowned by the pope as emperor. His empire based in modern France, the Low Countries and Germany expanded into modern Hungary, Italy, Bohemia, Lower Saxony and Spain. He and his father received substantial help from an alliance with the Pope, who wanted help against the Lombards. The pope was officially a vassal of the Byzantine Empire, but the Byzantine emperor did (could do) nothing against the Lombards.
To the east Bulgaria was established in 681 and became the first Slavic country. The powerful Bulgarian Empire was the main rival of Byzantium for control of the Balkans for centuries and from the 9th century became the cultural center of Slavic Europe. Two states, Great Moravia and Kievan Rus', emerged among the Western and Eastern Slavs respectively in the 9th century. In the late 9th century and 10th century, northern and western Europe felt the burgeoning power and influence of the Vikings who raided, traded, conquered and settled swiftly and efficiently with their advanced sea-going vessels such as the longships. The Hungarians pillaged mainland Europe, the Pechenegs raided eastern Europe and the Arabs the south. In the 10th century independent kingdoms were established in Central Europe, for example, Poland and Kingdom of Hungary. Hungarians had stopped their pillaging campaigns; prominent nation states also included Croatia and Serbia in the Balkans. The subsequent period, ending around 1000, saw the further growth of feudalism, which weakened the Holy Roman Empire.