Note: Ancestor of Matilda of Flanders, Queen Consort of William the Conqueror.
Sources
Royal Ancestry by Douglas Richardson Vol. V, page 494
From Wikipedia:
Emma of Altdorf, also known as Hemma, (808 - 31 January 876) was the daughter of Welf I of Altorf, Count of Altorf. Her mother was Heilwig of Saxony (Duchess of Bavaria), the daughter of Count Isanbart. Hemma was the wife of King Louis the German, and was became Queen consort of Eastern Francia. Louis was a grandson of Charlemagne and the third son of the succeeding Frankish Emperor Louis the Pious and his first wife, Ermengarde of Hesbaye.
In 827 at Regensburg, Emma married Louis the German, son of the Carolingian Emperor Louis, and stepson of Emma's sister. She was thus from 817-843 Queen consort of Bavaria. She was given in 833, by her husband Louis, Obermünster Abbey in Regensburg.
She is described as having had great qualities: an uncommon courage and talent, deployed on more than one occasion. In particular, she led an army against Adelchis of Benevento, when he revolted against Louis the German; it is said that, frightened by the arrival of the Queen, the traitor fled by boat to seek safety in Corsica. The Annals of Saint-Bertin however reproach Emma for a pride which displeased the people of Italy.
With the Treaty of Verdun in 843, she became Queen Consort of Eastern Francia. She died on 31 January 876, and was buried in St. Emmeram's Abbey, Regensburg.
Emma's sister was Judith (sometimes called Judith of Bavaria), who was the second wife of Emperor Louis the Pious, and by marriage Queen and Empress of the Franks.
Hemma (Emma) and King Louis 'the German' had seven children:
? Hildegard (828 - 856);
? Carloman (829 - 880);
? Irmgard of Chiemsee also known as Ermengard (died 866). Louis, having established two of his other daughters as abbesses of convents, appointed Irmgard (also known as Ermengard) to govern first the monastery of Buchau and then the royal abbey of Chiemsee in Bavaria. She is commemorated as a saint on 16 July;