A brief civil war was put down by Otto I, Holy Roman Emperor.
Otto I -LRB- 23 November 912 -- 7 May 973 -RRB- , traditionally known as Otto I the Great -LRB- Otto I. der Große -RRB- , was German king from 936 and emperor of the Holy Roman Empire from 962 until his death in 973 .. Holy Roman Empire. Holy Roman Empire. German king. Kingdom of Germany. German. Germans. He was the oldest son of Henry I the Fowler and Matilda .. Matilda. Matilda of Ringelheim. Henry I the Fowler. Henry the Fowler. Otto inherited the Duchy of Saxony and the kingship of the Germans upon his father 's death in 936 .. Duchy of Saxony. Duchy of Saxony. He continued his father 's work of unifying all German tribes into a single kingdom and greatly expanded the king 's powers at the expense of the aristocracy .. German. Germans. Through strategic marriages and personal appointments , Otto installed members of his family in the kingdom 's most important duchies .. This reduced the various dukes , who had previously been co-equals with the king , to royal subjects under his authority .. Otto transformed the Roman Catholic Church in Germany to strengthen royal authority and subjected its clergy to his personal control .. Roman Catholic. Roman Catholic. Roman Catholic Church. Roman Catholic Church. After putting down a brief civil war among the rebellious duchies , Otto defeated the Magyars at the Battle of Lechfeld in 955 , thus ending the Hungarian invasions of Western Europe .. Magyars. Magyars. Battle of Lechfeld. Battle of Lechfeld ( 955 ). Hungarian invasions of Western Europe. Hungarian invasions of Europe. The victory against the pagan Magyars earned Otto a reputation as a savior of Christendom and secured his hold over the kingdom .. Magyars. Magyars. pagan. pagan. Christendom. Christendom. By 961 , Otto had conquered the Kingdom of Italy and extended his realm 's borders to the north , east , and south .. Kingdom of Italy. Kingdom of Italy ( medieval ). The patronage of Otto and his immediate successors facilitated a so-called `` Ottonian Renaissance '' of arts and architecture .. Ottonian. Ottonian dynasty. Ottonian Renaissance. Ottonian Renaissance. Following the example of Charlemagne 's coronation as `` Emperor of the Romans '' in 800 , Otto was crowned Holy Roman Emperor in 962 by Pope John XII in Rome .. Holy Roman Emperor. Holy Roman Emperor. Charlemagne. Charlemagne. Pope John XII. Pope John XII. Otto 's later years were marked by conflicts with the papacy and struggles to stabilize his rule over Italy .. Reigning from Rome , Otto sought to improve relations with the Byzantine Empire , which opposed his claim to emperorship and his realm 's further expansion to the south .. Byzantine Empire. Byzantine Empire. To resolve this conflict , the Byzantine princess Theophanu married his son Otto II in April 972 .. Otto II. Otto II, Holy Roman Emperor. Theophanu. Theophanu. Otto finally returned to Germany in August 972 and died at Memleben in May 973 .. Memleben. Memleben. Otto II succeeded him as Holy Roman Emperor .. Otto II. Otto II, Holy Roman Emperor. Holy Roman Emperor. Holy Roman Emperor