Excerpts from Books and Wikipedia
"As Conrad I, King of Franconia, lay on his deathbed, it was his enemy Henry, duke of Saxony, who received the dying king's blessing, in the hope that he would unite the people. . . . Saxony and Franconia, two of the four most important duchies, rallied behind him, but Swabia and Bavaria resisted. . . . but Henry was forced to invade Bavaria in 921, and after two campaigns, Arnulf, duke of Bavaria, agreed to similar terms. Henry's achievements include the conquest of Lorraine and their region's incorporation into his kingdom as the fifth important duchy. . . . He is widely accepted as the founder of the medieval German state and the founder of what eventually became the first Holy Roman Empire. His son Otto took over a much more unified confederation." [1001 Days]