Motte and Bailey Castle

Hello people.

My group has just started using ACKs since yesterday and are quite pleased with the system at the moment. However we have found it slightly 'lacking' if you could call it that in one aspect. There are really no rules in the book for Motter and Bailey castles. Since we are playing in a fantasy world which has a lot in common with 10th/11th century England that is a problem. So I did what any DM would do and made my own rules for it, based on the ones present. I came up with the following.

Using the prices for making ditches I came up with the following price list for motte sizes. This is ofcourse eyeballing it.

10 feet high Motte (Diameter 100 feet at base and 50 on top)*

20 feet high Motte (Diameter 120 feet at base and 60 on top)*

30 feet high Motte (Diameter 140 feet at base and 70 on top)*

40 feet high Motte (Diameter 160 feet at base and 70 on top)*

*The creation of a Motte also creates a normal ditch surrounding it and possibly a slightly raised area for the Bailey

These are untested but it is at least something.

With the other buildings I am slightly stumped however. I could simply cut prices in half and make them wood but the sizes would be very off and what would be the point of the pallisade then? My other idea for a wooden wall is as follows.

You take 1x earth rampart and slightly narrow it say 10 feet thick. This is the filling for your 2x pallisades you buy. This would give you a dirt filled in wooden wall for 2750G. Am I on the right track for a wooden castle or do you have other ideas?

All thoughts and comments are welcome.

Your prices aren't showing up for me?

10 feet high Motte (Diameter 100 feet at base and 50 on top)*          12500

20 feet high Motte (Diameter 120 feet at base and 60 on top)*          20000

30 feet high Motte (Diameter 140 feet at base and 70 on top)*          27500

40 feet high Motte (Diameter 160 feet at base and 70 on top)*          35000

*The creation of a Motte also creates a normal ditch surrounding it and possibly a slightly raised area for the Bailey

This time with prices.

Since you’ve used diameter, the shape you’re describing is a chunk of a cone, correct?

You can use the wall-building patterns, with the base prices from the earthen rampart, to calculate what it would cost to build that kind of earthwork. Use the cubic footage costs of the rampart, that is (one-eighth of one GP per cubic foot), and compare to wall price shifting as height adjusts to make it match the height penalty.

Doing this gets you the following prices for the mottes you listed: (Note: Feel free to round any or all of these!)

10 foot high motte: 45 814.89 cubic feet, so 5,726.86 gp
20 foot high motte: 131 946.89, so 16,493.36 gp
30 foot high motte: 269 391.57, so 33673.95 gp
40 foot high motte: 469 144.5, so 58,643.06 gp (Note: Based on the pattern, I assumed there was a typo here and it was supposed to have an upper diameter of 80 feet and not 70.)

We compare this to walls and remind myself that walls actually get cheaper per cubic foot once you go above 30’ high and I don’t remember why. I therefore judge the calculated price per cubic foot of dirt mounded to be fine for all of these (though the price per cubic foot doubles when building above 60’, so keep that in mind if you wanted to have 61’+ mottes.)

Interesting!

Wikipedia says

"The size of mottes varied considerably, with these mounds being 3 metres to 30 metres in height (10 feet to 100 feet), and from 30 metres to 90 metres in diameter (100 feet to 300 feet).[9] This minimum height of 3 metres (10 feet) for mottes is usually intended to exclude smaller mounds which often had non-military purposes.[10] In England and Wales, only 7% of mottes were taller than ten metres high; 24% were between ten and five metres, and 69% were less than five metres tall.[11]

...

artificial mottes had to be built by piling up earth; this work was undertaken by hand, using wooden shovels and hand-barrows, possibly with picks as well in the later periods.[26] Larger mottes took disproportionately more effort to build than their smaller equivalents, because of the volumes of earth involved.[26] The largest mottes in England, such as Thetford, are estimated to have required up to 24,000 man-days of work; smaller ones required perhaps as little as 1,000.[27] Contemporary accounts talk of some mottes being built in a matter of days, although these low figures have led to suggestions by historians that either these figures were an underestimate, or that they refer to the construction of a smaller design than that later seen on the sites concerned.[28] Taking into account estimates of the likely available manpower during the period, historians estimate that the larger mottes might have taken between four and nine months to build.[29] "

 

Hopefully that is useful data. Perhaps the 4 options should be

  • 10 feet high, 100 foot diameter
  • 30 feet high, 100 foot diameter
  • 10 feet high, 300 foot diameter
  • 30 feet high, 300 foot diameter

With some formulas to calculate other choices?

The Castle Hill motte is described like this

"The motte is a large, circular mound of chalk, approximately 25m in height and 90m in diameter at the base. At the summit is a sub-rectangular platform about 25m in diameter surrounded by a bank of chalk rubble approximately 2m in height with an opening on the north west side. The platform would originally have supported a timber tower, evidence for which will survive below the ground surface, and it is likely that the bank represents the footing of a wall or timber palisade. The base of the motte is encircled by a ditch about 18m - 20m wide which remains open to a depth of between 5m and 6m, and enclosing this on the north side is a very large double bank and ditch."

Translating to feet - 270 foot diameter at the base, 75 feet high, 75 foot diameter at the top.