Cardo & Decumanus

The idea of a grid as a system for planning can be traced back to the Ancient Romans. When the Romans set out to build a new castrum in a land that they had conquered, they would typically start out with a strategic center point from which they would establish two main roads, a Cardo (North- South) and a Decumanus (East West). These two streets served as the main two streets that would then expand into a grid that will eventually become many of the European cities that we know and love.

This concept became deeply engrained in European city and town planning and eventually colonial America. Therefore it is no surprise that the two main streets in Orwigsburg are a true Cardo (Warren Street) and Decumanus (Market Street). It is also highly appropriate that the first Schuylkill County Courthouse be built on a lot at the intersection of these streets facing a beautiful town square.


The Position of Orwigsburg

When taking a first glance at the plan of Orwigsburg, it seems to be randomly tilted with no reference to any sort of cardinal direction. However it seems that based on me research, there is much more behind the 20 degree tilt East of North. Historically, many towns and settlements were “oriented” to the North. This determination could be made in a few ways, one of which was to use a compass. However, a compass’ North does not actually point to true north. It actually points to magnetic north. Interestingly, science tells us that the location of magnetic north has moved over time and continues to move to this day as it is part of a glacier in the arctic circle. Therefore, I hypothesize that the orientation of early towns has moved with magnetic north over time.

This can be seen in Orwigsburg as the rear projection of magnetic north at the time of Orwigsburg’s founding was indeed very close to 20 degrees East of North.