Ethelfleda (alternative spelling Aethelfled, Æthelfleda or Æthelflæd) (c.872-918) was the eldest daughter of King Alfred the Great of Wessex and his wife Ealhswith. She was born around AD 872. She married Aethelred or Ethelred, later the ealdorman or earl of Mercia, in about 886, and had one daughter, Aelfwynn. When she was 15, while she was traveling to Mercia to get married, her band was attacked by the Danes, attempting to kill Aethelflaed and break off the alliance. Though half her company perished in the first attack, AEthelflaed used an old trench as a fortress, and defeated the Danes. While her husband was alive, she signed agreements, leading some to think that she was the real leader. On her husband's death in 911 after the Battle of Tettenhall, she was elevated to the status of "Lady of the Mercians". This title was not a nominal position; she was a formidable military leader and tactician. Ethelfleda ruled for five years from the newly fortified capital at Stafford, and under her reign, it is likely that the English county of Staffordshire first came into being. She fortified her existing borders and re-took Derby. She died in 918, and is buried at Gloucester. She was joint lady of the Mercians along with her young daughter Aelfwynn. She was succeeded as ruler of Mercia by her brother, King Edward the Elder.