Æthelflæd Æthelflæd , Lady of the Mercians , ( d . 12 June 918 ) was the eldest daughter of Alfred the Great , king of the Anglo - Saxon kingdom of Wessex , and his queen , Ealhswith . Æthelflæd was born at the height of the Viking invasions of England . Her father married her to Æthelred , Lord of the Mercians . After his death in 911 she ruled Mercia until her own death in 918 . The " Anglo - Saxon Chronicle " referred to her as the " Myrcna hlæfdige " , " Lady of the Mercians " . Background and family . By the end of the 8th century the petty Anglo - Saxon kingdoms of the early settlement period had been consolidated into four large ones , Wessex , Mercia , East Anglia and Northumbria . In the early 9th century Wessex became the dominant kingdom under Æthelflaed ' s great - grandfather , Egbert . In the middle of the century England came under increasing attack from Viking raids , culminating in the invasion by the Great Heathen Army in 865 . By 878 the Vikings had destroyed East Anglia , Northumbria , and Mercia , and nearly conquered Wessex , but the West Saxons fought back under Æthelflaed ' s father , Alfred the Great , and achieved a decisive victory at the Battle of Edington . Alfred and the Viking leader Guthrum then agreed on a division that gave Alfred western Mercia , while eastern Mercia was incorporated into Viking East Anglia . Æthelflæd is mentioned by Alfred ' s biographer Asser , who calls her the first - born child of Alfred and his Mercian bride Ealhswith and a sister to Edward , Æthelgifu , Ælfthryth and Æthelweard . < / div > Marriage to Æthelred . Æthelflaed was already married to Æthelred , then ealdorman of Mercia . Æthelred and Æthelflæd are recorded as having had one daughter , Ælfwynn . Æthelstan , the son of Edward the Elder and the grandson of Alfred , was brought up in their court . Near the end of the reign of Alfred the Great , Æthelred and Æthelflæd were requested by Werferth , the Bishop of Worcester , to fortify the town , in return for which they shared the rents and other profits which had belonged to the bishop . Lady of the Mercians . Æthelflæd established garrisons in Hereford and Gloucester before 914 and repaired the old walls of Chester in 907 . In 910 she built her first fortress ; since her husband took no part in the campaign against the Danes , some scholars suggest that she was the real leader of the Mercian people . On her husband ' s death in 911 after the Battle of Tettenhall , she was recognised as the " Lady of the Mercians " . This was not a purely honorific title ; Æthelflæd was a formidable military leader and tactician and ruled for eight years . Upon succeeding her husband , she began to plan and build a series of fortresses in English Mercia , ten of which can be identified : Bridgnorth ( 912 ) ; Tamworth ( 913 ) ; Stafford ( 913 ) ; Eddisbury ( 914 ) ; Warwick ( 914 ) ; Chirbury ( 915 ) ; Runcorn ( 915 ) . Three other fortresses , at Bremesburh , Scergeat and Weardbyrig , have yet to be located . Æthelflæd allied herself to her brother Edward the Elder . Historian Sir Frank Stenton said that Edward was able to achieve " the outstanding feature of his reign " , the move against the occupying Danes in the south of England , due to being able to rely upon Æthelflæd . In 916 she led an expedition into Wales to avenge the murder of a Mercian abbot , and succeeded in capturing the wife of the king of Brycheiniog . Edward the Elder issued coinage with novel reverses of extraordinary designs , and it is speculated that this series of coinage was for circulation in the part of Mercia under the rule of Edward and his sister , with the design of the coinage perhaps showing the influence of Æthelflæd . Death and legacy . In 918 , the people of the region around York promised to pledge their loyalty to Æthelflæd , probably in order to secure her support against Norse raiders from Ireland , but she died on 12 June 918 , less than two weeks before the city was able to pay homage to her . She was succeeded as Lady of the Mercians by her daughter , Ælfwynn , but six months later Edward deposed her and took Mercia under his personal control . According to the Parker Chronicle ( Manuscript A of the " Anglo - Saxon Chronicle " ) , which was strongly sympathetic to Edward , " all the people in the land of the Mercians who had been subject to Æthelflæd turned to him ; and the kings among the Welsh , Hywel and Clydog and Idwal , and all the Welsh people sought to have him as their lord " . Hywel Dda was king of Dyfed in south - west Wales , Clydog ap Cadell probably king of Powys in the north - east , and Idwal ab Anarawd king of Gwynedd in the north - west . Gwent in south - east Wales was already under West Saxon lordship , but in the view of historian T . M . Charles - Edwards this passage shows that the other Welsh kingdoms were under Mercian lordship until Edward took direct power by deposing Ælfwynn . Æthelflæd died at Tamworth , Staffordshire and was buried with her husband in St Oswald ' s Priory , Gloucester , which they had established . A statue of her was erected outside Tamworth Castle in 1913 to commemorate the millennium of her construction of the burh of Tamworth .