01-15-2019, 01:49 PM
The following is scribbled quickly without too much use of 'probable', 'maybe' etc.
There were probably simple rules/guidelines for the camp layout which a 'surveyor' would know for the size of his force. Key consideration would be the orientation of the area assigned to each contubernium relative to the short or long sides of the camp - expect this would be decided before the force started to march. Once this is decided the total space, the lengths of the camp sides, placing of tented areas, intervallum and the dividing 'clear areas' or interior roads etc. are all predetermined.
So, arrive at camp site; mark out the short side and deploy two groma at each end. The mid-point of this side is the site for the Porta Pratoria. The side is marked at the outer edge of the proposed rampart. This is because the first job for the construction crew is the cutting of turves for the rampart. It makes little sense to cut turves inside the camp or under the rampart. The line for the sides was probably marked as a visual aide by the first turves, i.e. at the outer edge of the rampart. The same could be done for the midline of the ditch but this probably not really necessary for an experienced force. Using the turves to mark out the camp elements is quite simple, effective and, once done, releases the surveying crew to move elsewhere.
The rounded corners are simple to engineer using a length of string: place one end at the groma and run it back down the short side; now release the end at the groma and rotate it at 90 degrees into the interior of the camp, i.e. the string is perpendicular to the camp side; fix the interior end of the string and then rotate the other end to describe on the ground a constant radius curve which is the outer margin of the curved corner of the rampart - lay turves as the string rotates. Simple, practical and the four corners of the camp will describe the same arc if one piece of string is used.
Now use groma and sighting staffs to sight along the proposed long sides (the groma if used correctly will give 90 degree angle between short and long sides). Mark out using turves as they become available.
It isn't necessary nor desireable to complete the survey of the full circuit of the camp before ditch excavation and rampart building start - the surveying can continue quite simply down the long sides as and when required. An obvious benefit is that the defences are built quickly - the long sides are extended - by the soldiers as they arrive in the camp. Having an open-ended construction technique also allows flexibility in the overall size of the camp, i.e. the long sides can shrink or grow depending on the number of units in the force. Plus, without the final short-side yet surveyed or built then the force still marching can simply flood into the camp and set-up tents etc. where they normally do.
One of the last acts would be to seal off the long sides with the construction of the remaining short side, that which contains the Porta Decumana.
Two groma, some sighting staffs, a length of string and lots of turves - all very simple technology and techniques. Simple enough for a few bright soldiers to be taught how to use the groma etc. - no need for a well-educated man to accompany each force in the field; save him for teaching, building forts, ports, towns, temples, planning roads and for deploying with very large armies requiring large camps.
To state the obvious, there is one prerequisite that all armies through time rely upon, experienced men. Without them then the description above would probably be untenable or take a long time.
Some answers to questions above:
1) How long to build a camp = 2.5 to 3 hours for all force sizes, for nearly all camp sizes and metrics (ditch depth, etc.).
2) The Romans used relatively small numbers of well-trained, well-equipped men to conquer and control. During daylight hours these samll forces were usually capable of defending themselves against much larger numbers of enemies. However, without a night-time, defensive stronghold - the marching camp - the small Roman force would be overwhelmed. Darkness was the legionary's nemesis, not marching in columns during daylight - usually!
3) How many turves for a camp? One legion, builds a camp 276 x 351 m in size, using 30% of the force, within 2.42 hours. A rampart built of walls two turves thick, infilled with soil from the ditch, 2 m wide, 1.1 m high and with a fighting platform 1.2 m wide would require 520 turves, each of volume 0.01945075 cubic metres.
If you like playing with a few numbers relating to Romans on campaign then I can recommend a spreadsheet here and an accompanying, descriptive document here. You need the document to use the spreadsheet. Splendid stuff!
There were probably simple rules/guidelines for the camp layout which a 'surveyor' would know for the size of his force. Key consideration would be the orientation of the area assigned to each contubernium relative to the short or long sides of the camp - expect this would be decided before the force started to march. Once this is decided the total space, the lengths of the camp sides, placing of tented areas, intervallum and the dividing 'clear areas' or interior roads etc. are all predetermined.
So, arrive at camp site; mark out the short side and deploy two groma at each end. The mid-point of this side is the site for the Porta Pratoria. The side is marked at the outer edge of the proposed rampart. This is because the first job for the construction crew is the cutting of turves for the rampart. It makes little sense to cut turves inside the camp or under the rampart. The line for the sides was probably marked as a visual aide by the first turves, i.e. at the outer edge of the rampart. The same could be done for the midline of the ditch but this probably not really necessary for an experienced force. Using the turves to mark out the camp elements is quite simple, effective and, once done, releases the surveying crew to move elsewhere.
The rounded corners are simple to engineer using a length of string: place one end at the groma and run it back down the short side; now release the end at the groma and rotate it at 90 degrees into the interior of the camp, i.e. the string is perpendicular to the camp side; fix the interior end of the string and then rotate the other end to describe on the ground a constant radius curve which is the outer margin of the curved corner of the rampart - lay turves as the string rotates. Simple, practical and the four corners of the camp will describe the same arc if one piece of string is used.
Now use groma and sighting staffs to sight along the proposed long sides (the groma if used correctly will give 90 degree angle between short and long sides). Mark out using turves as they become available.
It isn't necessary nor desireable to complete the survey of the full circuit of the camp before ditch excavation and rampart building start - the surveying can continue quite simply down the long sides as and when required. An obvious benefit is that the defences are built quickly - the long sides are extended - by the soldiers as they arrive in the camp. Having an open-ended construction technique also allows flexibility in the overall size of the camp, i.e. the long sides can shrink or grow depending on the number of units in the force. Plus, without the final short-side yet surveyed or built then the force still marching can simply flood into the camp and set-up tents etc. where they normally do.
One of the last acts would be to seal off the long sides with the construction of the remaining short side, that which contains the Porta Decumana.
Two groma, some sighting staffs, a length of string and lots of turves - all very simple technology and techniques. Simple enough for a few bright soldiers to be taught how to use the groma etc. - no need for a well-educated man to accompany each force in the field; save him for teaching, building forts, ports, towns, temples, planning roads and for deploying with very large armies requiring large camps.
To state the obvious, there is one prerequisite that all armies through time rely upon, experienced men. Without them then the description above would probably be untenable or take a long time.
Some answers to questions above:
1) How long to build a camp = 2.5 to 3 hours for all force sizes, for nearly all camp sizes and metrics (ditch depth, etc.).
2) The Romans used relatively small numbers of well-trained, well-equipped men to conquer and control. During daylight hours these samll forces were usually capable of defending themselves against much larger numbers of enemies. However, without a night-time, defensive stronghold - the marching camp - the small Roman force would be overwhelmed. Darkness was the legionary's nemesis, not marching in columns during daylight - usually!
3) How many turves for a camp? One legion, builds a camp 276 x 351 m in size, using 30% of the force, within 2.42 hours. A rampart built of walls two turves thick, infilled with soil from the ditch, 2 m wide, 1.1 m high and with a fighting platform 1.2 m wide would require 520 turves, each of volume 0.01945075 cubic metres.
If you like playing with a few numbers relating to Romans on campaign then I can recommend a spreadsheet here and an accompanying, descriptive document here. You need the document to use the spreadsheet. Splendid stuff!
