Equally numerous are the remains of Roman camps, constructed with great engineering skill. Even when it was necessary to remain stationary for a very brief period, the Romans were accustomed to surround the space to be occupied by the soldiers' tents by an earthen rampart with stakes at the top (_agger_ or _vallum_), which was in turn surrounded by a fosse or trench (_fossa_), usually nine feet deep and twelve broad. The spot selected was always one that commended itself from its defensive capacities, and therefore could not be overlooked, and had a command of water. The streets were sometimes as much as a hundred feet broad, with a public meeting-place or _forum_ near the general's tent, which was usually pitched on the highest ground. There was a vacant space of two hundred feet between the tents and the ramparts called the _intervallum_. The shape of the camp in later times varied according to the nature of the ground, although in the days of the Roman republic it was as a rule rectangular. Of these temporary camps the most perfect is that situated near Kirkboddo, five miles to the south-east of Forfar. It was probably constructed by Agricola; all its six gates exist, and the entrenchment, even now, seems to have lost but little of its original height. It is about two thousand two hundred and eighty feet in length, and one thousand and eighty in breadth; and, apparently because it was necessary to find lodging for more men than the camp was originally intended to hold, there is a _procestrium_ or enclosure without the south-east angle of about one hundred thousand square feet. Permanent camps, which were smaller than the temporary camps, soon lost their original features and grew into towns. The establishment of an infirmary (_valetudinarium_), a farriery (_veterinarium_), and a forge (_fabrica_) within the rampart were quickly followed by the settlement of a civilian population, and the birth of trades and industries. In many of the English towns, which by the termination _cester_ or _chester_ or the prefix _caer_ betray their Roman origin, hardly a trace of the original Roman camp is to be found, but during the period of the Roman occupation of Britain the military element in them was probably in the ascendant. [Illustration: ROMAN URNS FOUND IN ENGLAND. (_From the British Museum._) 1. Urn of yellow pottery--height, 12½ in.; greatest diameter, 13 in. 2. Urn of grey pottery found at Colchester--11½ x 9. 3. Urn of red and grey pottery, found at Littleton Farm--13 x 12. 4. Urn of grey pottery, found in Huntingdonshire--height, 11½ in.; width at mouth 4¾ in. 5. Urn of yellow pottery, found in the Lea--height, 10½; greatest diameter, 10.] [Illustration: GLASTONBURY ABBEY. (_See p._ 31.)] CHAPTER III. THE FOUNDATION OF THE ENGLISH KINGDOMS AND THEIR CONVERSION TO CHRISTIANITY.