But undoubtedly the great centres of defensive strength lay in those towns which the Romans had formerly fortified, and the inclusion of their masonry walls in the borough boundary immensely augmented their efficiency, as is exemplified at York, Lincoln, and Chester. Around villages and farmsteads the defences probably consisted of a ditch, a vallum surmounted by a turf wall, a palisading of thick stakes, or even a hedge. That the latter was a mode of defence in the earlier part of the Saxon Period is proved by an insertion in the Old English Chronicle under the year 547--where Ida of Northumbria is said to have built _Bebban burh_, _i.e._ Bamborough,--that it was first enclosed with a hedge, and subsequently with a stone wall. Illuminations in Saxon MSS. representing fortified towns invariably depict stone walls with battlements; but, again, it may be that these are Roman, and crenellated walls are extremely ancient, being represented upon the Nineveh marbles. In the illustration from the Caedmon MS. given here true battlements are depicted by the Saxon artist, while a similar attempt has also been made in Harl. MS. 603--a battlemented parapet being evidently intended. [Illustration: BATTLEMENTED PARAPET SHOWN IN CAEDMON'S PARAPHRASE; MS. IN BODLEIAN LIBRARY.] [Illustration: BATTLEMENTS SHOWN IN HARL. MS. 603. (An Anglo-Saxon MS. of the Psalms.)] Ida "wrought a burh" at Taunton (before 721), and Alfred built many burhs against the Danes. His son, Edward the Elder, and Ethelfleda, the Lady of the Mercians, were yet more energetic in raising these defences. To Edward the burh at Witham, now unfortunately in process of demolition, and also that at Maldon are attributed, while Ethelfleda was responsible for those at Stafford and Tamworth in 913, and at Warwick in 914. In the absence of rebutting evidence we are undoubtedly justified in assuming that these burhs were simply replicas of the conjectured method of fortification pursued by the Saxons; the belief is strengthened by the remains at Maldon and Witham, where wide rectangular enclosures are found surrounded by earthen ramparts and external fosses. A difficulty, however, arises when we consider the two burhs erected at Nottingham. No rectangular enclosures have been discovered there, and it seems probable that the word simply signifies that two forts were erected to protect the bridge which passed over the Trent at this point, similar perhaps to the mounds of earth at Bakewell and Towcester, which are supposed to date from the same period.