Such was old Cambridge; with its eleven ancient parishes of St. Peter, St. Giles, St. Clement, Holy Trinity, St. Michael, St. Mary (the greater), St. Edward, St. Benet, St. Botolph, All Saints, and St. John (which was destroyed to make room for King's College). Before the twelfth century closed three more churches were added, those of the Holy Sepulchre, of St. Peter (now St. Mary's the less) outside the "Trumpington Gate," of St. Andrew (the greater) outside the Barnwell Gate, and St. Andrew (the less) in the detached suburb which grew up round the great "Abbey" (really an Augustinian Priory) of Barnwell. Old Cambridge probably owed its constitution--(quite possibly its very existence)--to the genius with which "the Children of Alfred," Edward the Elder and his Sister, the "Lady of the Mercians," reorganised the Midlands after the great cataclysm of the Danish wars, which in the previous generation had swept over the district, obliterating all earlier landmarks and boundaries. One pirate horde, under the most renowned of all their chieftains, Guthrum--the deadliest antagonist, and afterwards the most faithful ally, of our great Alfred,--had for a space settled themselves in Cambridge, and from that strategic position overawed East Anglia on the one hand and Mercia on the other.[2] [Footnote 2: The kingdom of Mercia comprised the Midlands, and was (roughly) bounded on the north by the Humber and Mersey, on the west by Wales, on the south by the Thames, and on the east by the Cam and the Lea.] The Cambridge which they sacked was not, however, as it would seem, the later mediaeval town which we have been already considering, but a much smaller stronghold on the western bank of the River, comprising what is now known as "Castle End," and is still sometimes called "the Borough" _par excellence_. At this point the Cam, one bank or other of which is usually swampy even now, and was actually swamp in early days, is touched by higher and firmer ground on both sides. The height to the west is quite respectable, rising some eighty feet above the stream. Here, therefore, and here alone, was there of old any convenient passage-way for an army; the river elsewhere forming an almost insuperable barrier to military operations, from the Fens almost to its source. Such a site was sure to be amongst the earliest occupied; and we find, accordingly, that both Romans and Anglo-Saxons (presumably Mercians) successively held it. Most probably it was also a British site; but the great Castle mound, which earlier antiquaries attributed to the Britons, has been shown by Professor Hughes to be, mainly at least, a Norman work.