She was the third child of Conrad II (1159–1210), Margrave of Lusatia, and his wife, Elisabeth (c. 1153 – 1209), the daughter of Mieszko III the Old (1126–1202), Duke of Poland.
[2] Ersch and Gruber had this to say about Agnes and her husband:[3] Henry took possession of Otto's territories after the latter died without heir at the Harzburg in 1218, after a turbulent reign.
He handed the Imperial Regalia to Frederick II and retired to Brunswick, where he spent the rest of his life in peace.
In 1223, he declared that Otto the Child, the only son of his brother William would be the sole heir of the Welf allodial possessions in Saxony.
Henry married his daughter Agnes to Duke Otto the Illustrious of Bavaria and her sister Irmengard to Herman of Baden.