<P> The unsuccessful second siege of Constantinople (717) weakened the Umayyad dynasty and reduced their prestige . In 722 Don Pelayo, a nobleman of Visigothic origin, formed an army of 300 Astur soldiers, to confront Munuza's Muslim troops . In the battle of Covadonga, the Astures defeated the Arab - Moors, who decided to retire . The Christian victory marked the beginning of the Reconquista and the establishment of the Kingdom of Asturias, whose first sovereign was Don Pelayo . The conquerors intended to continue their expansion in Europe and move northeast across the Pyrenees, but were defeated by the Frankish leader Charles Martel at the Battle of Poitiers in 732 . The Umayyads were overthrown in 750 by the' Abbāsids, and, in 756, the Umayyads established an independent emirate in the Iberian Peninsula . </P> <P> 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 . </P> <P> 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 centre of Slavic Europe . The Empire created the Cyrillic script during the 10th century AD, at the Preslav Literary School . Two states, Great Moravia and Kievan Rus', emerged among the Slavic peoples respectively in the 9th century . In the late 9th and 10th centuries, 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 seagoing vessels such as the longships . The Hungarians pillaged mainland Europe, the Pechenegs raided Bulgaria, Rus States and the Arab states . In the 10th century independent kingdoms were established in Central Europe including Poland and the newly settled Kingdom of Hungary . The kingdoms of Croatia and Serbia also appeared in the Balkans . The subsequent period, ending around 1000, saw the further growth of feudalism, which weakened the Holy Roman Empire . </P> <P> In eastern Europe, Volga Bulgaria became an Islamic state in 921, after Almış I converted to Islam under the missionary efforts of Ahmad ibn Fadlan . </P>

When did the vikings first invade europes mainland