Monumental arches also played a role in the organisation of space and the regulation of movement of people within the town (MacDonald 1986: 74-6). Arches were mechanisms of transition and also connected areas of the town (ibid.: 32, 74). Evidence from Rome shows that monumental arches were often decorated with scenes and images celebrating the emperors and important military victories (J. Ward-Perkins 1981: 429-30). There were sometimes four-square arches (quadrifrons) positioned at armature junctions; these structures were also sometimes placed at spots where significant actions had taken place in the past (ibid.: 87-91). Very few monumental arches are known in Britain, but it appears that the Balkerne Gate in the town walls at Colchester was originally a monumental arch prior to the construction of the defences (P. Crummy 1984: 15,122), whereas at Verulamium, it seems that three monumental arches marked boundaries of earlier forms of the settlement (Frere 1983: 75-9; Wheeler and Wheeler 1936: 76-8, 129). Another arch is known from London, represented by monumental stone reused in a fourth-century section of the town wall (Blagg 1980).
It appears that the identified examples did undergo changes in the late Roman period. The remains of the arches at Verulamium are very scanty because of heavy robbing, which probably took place within the late Roman period (Frere 1983: 75-9). This would indicate changes in the organisation of the town but there is also evidence of much activity taking place in the town at a contemporary date. A monumental arch in London is known only through the stonework used in later structures (T. Williams 1993), but its demolition certainly did not indicate the decline of the town.
World History
