FORTIFICATION. 143 



second higher up on their terraces. Fis^. 17 is a representation of the 

 Appian Gate, which is rennarkable as having certainly formed part of the 

 nnost ancient fortification, since the lower portions of the tower and the wall 

 are constructed of hewn stone. The superstructure, with the machicolis, is 

 of brick, and was built in the age of Aurelian ; while the two towers, sennicir- 

 cular in front, but square within and behind, date unquestionably from the 

 earlier middle ages. 



As to the temporary fortification of the ancients, their field intrench- 

 ments, it was very simple, owing to the mode of their warfare. Their 

 field fortification was confined mostly to the intrenchment of their camps, 

 and we have seen already that this intrenchment consisted merely of a 

 breastwork thrown up of earth, and secured with an abattis. In a camp, 

 however, which was to be occupied for some time, a permanent camp as it 

 was called, the intrenchment was made more endurincr, and so arranged 

 that the encamped force could resist a violent assault, or even sustain a 

 short siege. The fortifications of such a camp (pi. 41, Jig. 1) had then much 

 similarity to those of a city, consisting also of long walls broken at intervals 

 by flanking towers. The walls, with their battlements, were low, however, 

 and rested upon a mound of earth. At the junction of the mound and the 

 wall, to render the scaling of the last more difficult, was set a palisade 

 of sharp stakes connected by cross beams, and a similar palisade was 

 placed at the foot, so that the assailants, before they could approach to scale 

 the wall, were exposed for some time to the missiles of the defenders. At 

 the distance of 100 paces from the rampart, another smaller breastwork 

 was carried around the camp ; the space between the two was thickly 

 set with caltrops (pi. 51, Jig. 54). The towers were of the same 

 height as the rampart, and were used as stations for the projectile engines ; 

 wherefore the terreplein, which ran in rear of the rampart, was made 

 wider behind them. The winter camps were more solidly constructed, and 

 formed as it were little cities. They were designed mostly for protecting 

 the frontiers, and were provided with lofty stone watch-towers, which 

 served at the same time for magazines and as dwellings for the guard 

 cohorts (pi. 35, fig. 1). These watch-towers were no further distant from 

 each other than the range of distinct vision, and were protected by rows 

 of palisades and abattis. Signals were given from them at night by torches 

 and fire, and during the day by smoke, the meaning of the signals being 

 agreed upon beforehand. 



The Middle Ages. 



Fortification in the Middle Ages varied in general very little from that 

 of antiquity. The predominant activity of the higher and feudal nobility, 

 while the burgher class in the cities were even more and more estranged 

 from the profession of arms, caused the cities to remain open, or protected 

 at least only by a simple wall, while fortification proper was confined to the 

 castles of the knights and the citadels erected for the (iefence of the cities. 



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