Bertha (died 925) was the second illegitimate daughter of Lothair II, King of Lotharingia, by Waldrada. She was renowned to be beautiful, spirited, and courageous. Ambition, coupled with her influence, involved her husbands in many wars. She married firstly to Bosonid Theobald of Arles, by which she had: Boso and Hugh of Provence, later king of Italy. Her second husband was Adalbert II of Tuscany and her two sons, Guy and Lambert, both ruled Tuscany later. Guy's minority was spent under her regency. When Hugh desired to marry Marozia, the widow of his half-brother Guy, he tried to eliminate the descendants of his mother by her second husband. She also had a daughter Ermengard, who married Adalbert I of Ivrea.
