England now had peace for some twelve years. Alfred made good use of the interval in reorganising his army and strengthening the kingdom generally, so that when attacks were renewed in 892 he was much better prepared to meet them. In the autumn of that year two fleets coming from France arrived in England: one landed on the Limen (between Hythe and Romney Marsh), the other under the leadership of Hæsten (O.N. Hásteinn) at Milton in North Kent. Alfred's difficulties were increased by the fact that during the next four years the Danish settlers in Northumbria and East Anglia played a more or less actively hostile part, both by land and sea. The Danes showed all their old mobility and in a series of raids crossed England more than once--first to Buttington on the Severn (co. Montgomery), then to Chester, and on a third occasion to Bridgenorth in Shropshire. They met with a uniformly stout and well organised resistance under the leadership of Alfred, his son Edward the Elder, and his brother-in-law Aethelred of Mercia, and in the end they had to retire with no fresh acquisition of territory. For the most part they distributed themselves among the East Anglian and Northumbrian Danes, but those who had no cattle wherewith to stock their land took ship and sailed back to the Seine. There were no further attacks from abroad during Alfred's reign, but piratical raids made by the East Anglian and Northumbrian Danes caused him a good deal of trouble, and in order to meet them he definitely addressed himself to the long delayed task of equipping a fleet. The vessels were carefully designed according to Alfred's own ideas: they were larger, swifter and steadier than the Danish vessels and they soon showed their worth when more than 20 vessels with their crews were lost by the Danes in one year. It is interesting to note that these vessels were manned in part by Frisian sailors, probably because of the low ebb to which English seamanship had sunk. When once Edward the Elder's claim to the throne was firmly established in the battle fought at 'the Holm,' somewhere in South Cambridgeshire, he commenced, with the active co-operation of his brother-in-law Aethelred, ealdorman of Mercia, the great work of strengthening the hold of the English on Southern Mercia preparatory to an attempt to reconquer the Danelagh. Chester was rebuilt in 907. In 910 a fort was built at 'Bremesbyrig,' possibly Bromesberrow in Gloucestershire. Aethelred died in the next year, but his wife Aethelflæd, the 'Lady of the Mercians,' continued his work, and forts were built at 'Scergeat,' perhaps Shrewsbury, at Bridgenorth on the Severn, at Tamworth, and at Stafford in 912. In 914 Warwick was fortified, while in 915 forts were built at Chirbury in Shropshire and Runcorn in Cheshire.