For ten points, name this founder of the dynasty that bears his name.
The future Byzantine Emporer Romanus II was at one time betrothed to his niece Hedwig, and his son married Theophano, who was either the daughter of the same Romanus II or the niece of John Tzimices.  The son of Henry I, Duke of Saxony, he defeated the Magyars at the Battle of Lech in 955 and was crowned Holy Roman Emperor in 962.  For ten points, name this founder of the dynasty that bears his name.
The future Byzantine Emporer Romanus II was at one time betrothed to his niece Hedwig, and his son married Theophano, who was either the daughter of the same Romanus II or the niece of John Tzimices.  
Otto I