Grid Plan - Roman Grid

Roman Grid

Perhaps the most well-known grid system is that spread through the colonies of the Roman Empire. The idea of the archetypal Roman Grid was introduced to Italy first by the Greeks, with such information transferred by way of trade and conquest.

Although the grid was an idea present in Hellenic societal and city planning, it was not pervasive prior to the 5th century BC. However, it slowly gained primacy through the work of Hippodamus of Miletus, who slowly planned and replanned many Greek cities in accordance with this form. The concept of a grid being the ideal method of town-planning became widely accepted by the time of Alexander the Great. His conquests were a step in the propagation of the grid plan throughout colonies, some as far-flung as Taxila in Pakistan, that would later be mirrored by the expansion of the Roman Empire. The Greek grid had its streets aligned roughly in relation to the cardinal points and generally looked to take advantage of visual cues based on the hilly landscape typical of Greece and Asia Minor. This was probably best exemplified in Priene, in present-day western Turkey, where the orthogonal city grid was laid out according with respect to the cardinal points, on sloping terrain that struck views out towards a river and the aforementioned city of Miletus.

The Etruscan people, whose territories encompassed what would eventually become Rome (Rix cited in Woodward 2008), founded what is now the Italian city of Marzabotto at the end of the 6th century BC. It was based on Greek Ionic ideas, and it was here that the main east-west and north-south axes of a town (the decumanus maximus and cardo maximus respectively) could first be seen in Italy. According to Stanislawski, there is little evidence that the Romans adopted the Etruscan model at Marzabatto early in their expansion. Instead, the Roman Grid was spread around the Mediterranean and into northern Europe later on during "the late Republic and the early Empire" period that saw dissemination of the grid plan throughout this area.

The military expansion of this period facilitated the grid form becoming the standard, as Romans established "castra" firstly as military centres in their territories, some of which would develop into administrative hubs as well. Despite being similar in form to the Greek version of a grid, the Roman grid was ultimately designed on the basis of being practical. Firstly, Roman castra were often sited on flat land, especially in close proximity to or on important nodes like river crossings or intersection trade routes. The dimensions of the castra were often standard as well, with each of its four walls generally having a length of 2150 feet. Familiarity was the aim of such a standard form of town planning. As soldiers could be stationed anywhere around the Empire, way-finding would be a non-issue within established towns as there would be no variation from place to place. All would have the afore-mentioned decumanus maximus and cardo maximus at its heart, the intersection of which would form the forum. Around this intersection would be sited important public buildings in much the same way a Central Business District sits at the centre of modern day metropolitan areas. Indeed, such was the level of familiarity between towns that Higgins states soldiers "would be housed at the same address as they moved from castra to castra". Pompeii has been cited by both Higgins and Laurence as the best preserved example of the Roman grid.

Outside of the castra, large tracts of land were also divided in accordance with the grid within the walls. These were typically 2400 feet per side (called in Latin centuria), and contained 100 parcels of land (each called in Latin heredium). The decumanus maximus and cardo maximus extended from the town gates out towards neighbouring settlements. These were lined up to be as straight as possible, only deviating from their path due to natural obstacles that prevented a direct route.

While the imposition of only one town form regardless of region could be seen as an imposition of imperial authority, there is no doubting the practical reasoning behind the formation of the Roman grid. Under Roman guidance, the grid was designed for efficiency and inter-changeability, both facilitated by and aiding the expansion of their empire.