Æthelflæd had already fortified an unknown location called Bremesburh in 910 and in 912 she built defences at Bridgnorth to cover a crossing of the River Severn. In 913 she built forts at Tamworth to guard against the Danes in Leicester, and in Stafford to cover access from the Trent Valley. In 914 a Mercian army drawn from Gloucester and Hereford repelled a Viking invasion from Brittany, and the Iron Age Eddisbury hill fort was repaired to protect against invasion from Northumbria or Cheshire, while Warwick was fortified as further protection against the Leicester Danes. In 915 Chirbury was fortified to guard a route from Wales and Runcorn on the River Mersey. Defences were built before 914 at Hereford, and probably Shrewsbury and two other fortresses, at Scergeat and Weardbyrig, which have not been located.
æthelflæd had already fortified an unknown location called bremesburh in 910 and in 912 she built defences at bridgnorth to cover a crossing of the river severn in 913 she built forts at tamworth to guard against the danes in leicester and in stafford to cover access from the trent valley in 914 a mercian army drawn from gloucester and hereford repelled a viking invasion from brittany and the iron age eddisbury hill fort was repaired to protect against invasion from northumbria or cheshire while warwick was fortified as further protection against the leicester danes in 915 chirbury was fortified to guard a route from wales and runcorn on the river mersey defences were built before 914 at hereford and probably shrewsbury and two other fortresses at scergeat and weardbyrig which have not been located