One of the greatest legacies of the Pax Romana was the spread of Roman culture to Western Europe. Roman rule in the semi-civilized areas of Western Europe (Gaul, Britain, and Spain) and Augustus' establishment of peace during the Pax Romana meant that there were Roman troops permanently stationed in the provinces. This helped Romanize and civilize the provinces in the West in three ways. First, as the legionary camps became permanent settlements, merchants, families, and other sorts of camp followers settled down around them. In time, these army camp settlements became towns and cities, whose military origins are still reflected in Britain in such place names as Winchester and Lancaster (from the Latin word for camp, castra). After they were discharged from the army, legionaries, who were Roman citizens, and auxiliaries (non-citizen soldiers who received Roman citizenship after their terms of service) would often settle in these towns, marry local women, and raise their children as Roman citizens.
Along these lines, the peaceful conditions brought on by the Pax Romana, promoted the growth of native towns into cities. Those cities whose leading citizens copied Roman styles of dress, language, architecture, and local government would earn Roman citizenship for their towns. The poorer citizens would then follow the leading citizens' leads, thus encouraging the spread of Roman civilization that way. Finally, with extended periods of peace, the Roman army spent much of its time building an excellent system of some 51,000 miles of paved roads stretching across the empire. While these roads' original purpose was to facilitate the rapid movement of Roman troops to trouble spots, they also promoted trade and the influx of Italian merchants into the towns of the western provinces.
In these three ways, the western provinces saw the heavy Romanization of their towns and also nobles on country estates who felt they had some incentive to copy Roman ways for personal advancement. However, there were limits to Romanization. For one thing, it only happened to any great extent in Gaul, Britain, and Spain where there was no long established civilization in place before the Romans came. By contrast, the Eastern provinces were already heavily influenced by Greek culture in the cities and native cultures in the countryside. In a sense, the Roman Empire was a bi-cultural empire, with Greek language and culture dominant in the East and Roman language (Latin) and culture and dominant in the West. (Coins in the East were even struck with Greek inscriptions.) In both East and West, the influence of these respective cultures was mainly limited to the cities and barely touched the countryside.
However, despite the serious decline of cities in the West during the Middle Ages, Roman culture would survive in the Eastern Roman (Byzantine) Empire and thanks to the efforts of monks in the West who copied many works of Roman literature. As a result, there would be a resurgence of Roman culture during the Italian Renaissance where it would reassert itself as the foundation of Western Civilization.