Æthelflæd, or the Lady of Mercia, was the eldest child and daughter of King Alfred the Great of Wessex and his wife, Ealhswith. She grew up amid tumultuous battles between the English and the Vikings. At around age 16, she was married off to Æthelred, Lord of the Mercians, in a strategic alliance, as he submitted to the overlordship of her father, Alfred. Together, Æthelred and Æthelflæd made significant attacks on the Danes, or the Vikings, thus driving them out from large areas of England and reclaiming their land. She became the effective ruler of the kingdom when Æthelred fell gravely ill. Soon after his death, she took over as the sole ruler of Mercia. Known for her military strategy, she joined hands with her brother, Edward, who later took over as Edward the Elder, the King of Wessex. After conquering kingdoms such as Wales and Derby, she died before completing her campaign for Leicester.