Making Authentic Caligae
Cutting Pattern for the Valkenburg/Castleford Caliga
To make authentic caligae one must first find an authentic cutting pattern.  Above is illustrated
the best that I've so far located, taken from the book, "
Stepping Through Time", the cutting
pattern for the so-called Valkenburg/Castleford caliga and a pattern that I made for the Mainz
variant.  Click on the following link for an example of the Mainz variant:
Mainz.  More
illustrations of caligae from Mainz may be seen in "
Roman Military Equipment", by Bishop
and Coulston.  All caligae found are notable for their narrow straps.  This pattern also has
narrow straps going between the toes.  Single toe straps are shown in the
Bishop and
Coulston book.  The number of ankle straps varied from one to three.  Michel Feugere shows
a few of the possible variations on page 179 of his book, "
Weapons of the Romans".  More
information on the construction of roman shoes may be found
here.

I've recently acquired a couple more caligae references.  The Valkenburg style is described in
the book, "Romeins lederwerk uit Valkenburg Z.  H.".  The book is in dutch, but there are
plenty of photos and drawings.  The nailing patterns were much more varied than what I have
been using.  "Romische Lederfunde aus Mainz" shows both caligae and calcei finds from
Mainz.  This book has helped me to understand the unique lacing of the Mainz style.  Though
I drew my pattern with single straps about the toe, as is shown in Bishop and Coulston, V
shaped toe straps were perhaps more common.

[Update 6/27/09)] I have revised my Mainz caliga pattern, reducing the number of toe straps
to three on the big toe side and four on the opposite side.  This should result in caligae that
more closely resemble what is shown in the Mainz book.  Previously I followed what is shown
in Bishop and Coulston.  Here is the latest pattern:
Roman footwear is also notable for the use of nails to attach the soles.  Below is a common
nailing pattern that the Romans used.  Notice the similarity to that of a modern running shoe!
Valkenburg Nailing Pattern
In the cutting pattern I high-lighted certain parts in color.  Keep in mine this is from my
experience fitting caligae to my feet, what works for your feet may be different.  As drawn, the
pattern is too wide for my feet.  I've high-lighted in blue where I made the heel section of the
sole narrower.  Caligae should fit tight about the foot.  If you have wider feet then the pattern
may be just fine as it is.
The outside straps are drawn much too long.  This may be remedied by simply delaying the
cutting of the strap holes to last.  Cutouts that should be done last I've high-lighted in red.
To make sure that the straps come out long enough, I've shown in green where the straps
should be initially cut longer.
The first pair of caligae that I made from pattern from "Stepping through time" resulted in
shoes with too much material behind the heel.  For the new pattern I changed the back.  
Notice that the notch is gone.  The idea is now to simply fold the leather around the back of
the heel
Construction
First print out the pattern.  Then measure the length of your longest foot from the base of the
heel to the tip of your big toe.  The ratio of this measurement to the corresponding length of
the printed pattern gives the required magnification factor.  Most copy centers have machines
that can make enlargements from magnification factors taken to two decimal places.  This
gives a cutting pattern scaled to your feet.
From the bends cut out the out-soles.  Make sure to do a left and a right!  From the 5-6oz
leather cut out the insoles.  Some people make the insoles a bit smaller than the out-soles.  I
found that making them the same size worked find.
From 8-9oz leather cut-out the uppers.  Make sure that you cut a left and a right.  Do not cut
the red cutouts!  Play particular attention to the little semi-circular knobs at the joins between
horizontal and vertical straps.  Is it my opinion that these are not just decorative, but serve to
prevent the tearing of the thin straps.  To make these use a 1/8 inch round wood carving tool,
carefully working your way around the circumference of the knob. Use an edge beveler to
round the inside edges of the straps.
Next stitch together the backs.  Many types of stitches are possible, a simple cross stitch is
particularly easy to do, but this does not seem to be what the Romans preferred.  An edge
stitch, reinforced by a tacked-on strip of thin leather, appears to been very common:
If your particularly anal you could do both sides.  With the added reinforcing strips having the
edge stitch on just the outside appears to be sufficient.  The reinforcing strips are applied
using a simple running stitch, on both sides, over the edge seam.Notice now that after
stitching together the backs you're left with a small opening on the bottom.  There has been
some conjecture as to what to do here.  Leave it open or stitch it closed?  I prefer to have the
backs of my caligae closed.  Fold the leather around the curved back, trim of any excess, and
attach using a whip stitch.  I did not do exactly as Martin did, the leather seemed to be a bit
too stiff, but simply stitching the back to the rounded part of the middle layer seemed to do
the trick.

I no longer recommend simply glueing the out-sole.  While the in-sole may be safely glued
in-place, glue by itself, even with hobnails,  is not sufficient to keep the out-sole attached to
the upper.  The out-sole needs to be stitched on using either a tunnel stitch about the edge,
the hard way, or by a tunnel stitch between the upper surface of the out-sole and the upper,
the easier way.  Using a curved awl make a series of tunnels in the out-sole following the
edge.   An 1/8 inch from the edge is likely a good choice.   As the stitches in the upper will be
covered by the in-sole a simple tack stitch is fine there.  When sewing, use a flexible needle
to run the thread through a tunnel, up and down through the upper, and continue until you
have the entire stitch completed.  You may want to go through a few iterations tighting up the
thread till the upper and out-sole assembly is secure.  See below for details on the required
tools.  When glueing in the in-sole use spring clamps to hold everything together.  The
outsole, upper, and insole form a sandwich through which the nails are inserted.

Following the nailing pattern pound in the hobnails.  Roman reenactors in the USA have been
using 5/8 inch Tremont Cut Nails. Though of the right diameter and much better than say
carpet tacks, they look nothing like roman hobnails.  Roman hobnails are conical in shape.  
Recently I discovered a source of almost correct hobnails from
Le Prevo Leathers in the UK.  
My current pair of caligae use these.  To apply the nails first draw the nailing pattern on the
bottom of the outsole in pencil.  I found that the guide holes that were necessary when using
the Tremont cut nails was no longer required. The irregular cross section of the Tremont
nails tends to cause them to bend in unexpected directions.  You need some sort of anvil to
pound on.  There has been quite a debate on clinching of the nails.  Previously I was
definitely in the clinching camp, but now I'm not sure.  Roman caligae consisted of only three
layers, the out-sole, the upper, and an insole.  Walking on clinched nail ends is not
particularly comfortable.  The Le Prevo hobnails come with shorter shanks.  Using the layers
of leather that I did, 6mm out-sole, 3mm upper, and 2mm insole, gave plenty of room for the
nails.  The nail shank just poked into the insole without penetrating it.

Having forgone clinching of the nails, some additional means of attachment is a good idea.  
On the pair of caligae shown below I additional bit of security is provided by a zig-zag tunnel
stitch on the outside between the out-sole and the upper.  Due to the hardness of the bends
this is not an easy operation.  I did this about both the heel and the toe.  Curved awls and
either curved or flexible needles are needed.  Flexible steel needles, formed by a piece of thin
steel wire folded over into a loop and solder at one end are used to sitich through the tunnels.

We're almost done.  Put your feet in your new caligae and pinch the straps together.  Mark
with a pencil the location where they join together.  This will tell you how long the straps need
to be and where the lacing holes need to be.  Trim the straps and finish cutting the holes.
Finally, finish the leather with a generous coating of Neatsfoot oil.
Caligae are laced in a criss-crossed pattern.  Start by threading the leather lace from the
outside of the two outer-most straps at the toes.  The straps at the toes are an exception.  
Notice that there is one strap on the inside for four straps on the outside.  Just bunch these
four outside straps together against the single inside strap.  Then simply criss-cross the lace
going from strap to strap making tight Xs between the straps.  Tie the lace about your ankle
as you would any shoe.  Be careful when purchasing the lace.  Tandy appears to sell lace in
at least two thicknesses.  You want to use the larger lace that is about 1/8 inch by 1/8 inch
square.

When you're done you should have a pair of caligae like these:
Required Materials
One double shoulder 8-9oz (about 3mm thick) tooling leather is good for a couple of pairs of
caligae.
One 16oz (6mm thick) bend for the out-soles
one 5-6oz (2mm thick) shoulder for the insoles, and
one 2-3oz  (1mm thick or less) for the back reinforcement.
Waxed linen thread.  Recently on Roman Army Talk, RAT, there was described an alternative
to waxed thread, coating the thread with something called "shoe-maker's pitch".  I'm told that
this stuff is available in Germany, but since I have not been able to locate a supply of it here in
the states, I cannot say which is better, waxed or pitched thread.
Hobnails
Though carpender's glue would work, I now prefer E6000 (it's also waterproof).  You'll find it
at art supply stores.

Tools
Leather stitching is typically done with blunt needles.  Thread holes are made with a scratch
awl.  
Tandy leather has these.
Tunnel stitches usually require a
cuved awl to make the holes and either cured needles or
flexible needles.  I'm told that pig's bristles work as well.
Sharp knives to cut the leather.  I like to use an x-acto number 2 blade.
As described earlier, a 1/8 inch round wood craving tool makes short work out of cutting the
knobs in the uppers.
Some spring clamps.
A 16oz hammer and an anvil.  I recently acquired a
shoe-maker's anvil from RLQM.  It is
supported by the Hardy hole in my large 110lb anvil, but could just as well be supported by a
vise.

Here is a picture of my leather working tool set
Valkenburg/Castleford Caliga
Nailing Pattern
Back Seam
Edge Stitch for the Back
Seam
My latest
Caligae
Here is a vew of the back seam:
My New Caliga Pattern
Changes in my new caligae construction include:

1.  Use of thicker leather for the upper.  Those located in Europe have the advantage of being able to see
close up the genuine article.  It is the opinion of those who appear to be more familiar with this topic
than I am that the leather of the upper should be in the 3mm to 4mm thick range.  My next caligae will
therefore use 8-9oz leather instead of 5-6oz.

2.  I am going to try Martin Moser's method of stitching the lower back.  Stitching together the
"keystone", as shown on the original pattern left much too much material behind the heel.

3.  Instead of two pieces of 8oz leather glued together to make the outsole I am going to use a single
piece of 16oz bends.  This is specially compressed leather designed for such an application.  This is also
more correct as I am told that the calligae found have only a single piece of leather making the outsole.

4.  The use of real hobnails.
My Hobnails from Matt Luke have arrived!  Similar conical hobnails are now available from DSC.  
The difference between them and the Tremont nails, and the Le Prevo nails is quite noticable
(Tremont on the left followed by the Le Prevo hobnails, with Matt Luke's hobnails rightmost):
The progression of improvement is quite noticable.  Though still not quite right, the Le Prevo hobnails
look much more like
real roman hobnails.  The downside is that they are cast steel not forged.  In
contrast, those from Matt Lukes are spot on.
My latest Caliga
Back view
Here is a view of the bottom showing the Le Prevo hobnails:
Nailing
My new caligae on my feet
Front view
My leather working tools
After Action Report
I wore these caligae to the recent Fort Malden roman event in Canada.  Overall they worked out quite
well. Like any new pair of shoes the leather has stretched out a little bit making them somewhat more
comfortable to wear.  Two issues though:

The lower tabs going about the feet tended to slide back and forth.  I fixed this by replacing the laces
with longer ones and wrapping the lace around the tabs to secure them.  Comfort seems to be
improved as well.  See the photo below:
Old construction
Curved Awl for making tunnel stitches
I recently made a change to my construction.  Instead of glueing the out-sole and tunnel stitching about
the edge I now employ a tunnel stitch between the upper and the out-sole surfaces.  A pre-exquiste is
the need to soak the out-sole in warm water for a couple of hours.  At first I attempted the making of
the tunnels in the out-sole using curved awls.  After breaking every curved awl in my possession, I
switched over to a cut-off curved suture needle.  It turned out the this worked much better and I have
yet to break one of these.  I simply cut-off the eye and chucked the curved needle into an awl holder.  
The fabrication using tunnel stitching between the surfaces of the upper and the out-sole is not only
easier than tunnel stitching about the edge, a firmer construction is made.

The construction method using tunnel stitching is illustrated below:
Once the tunnels in the out-sole have been made the sewing itself is easier to do using flexible steel
needles.  Martin Moser sent some of these to me, as I've been unable to locate a source of supply.  
These should be easy to make as they consist of a peice of thin steel wire, about 26 gauge, folded
over into a loop and soldered at one end.

Here are a pair of caligae that I recently made for a friend.  These have the out-soles attached to the
uppers using the method of tunnel stitching previously described.
A variant of the Mainz Caliga
Sole Construction using Tunnel Stitching
Making the Mainz Caligae
I've just started the process of building a pair of Mainz variant caligae.  I like to transfer the paper
pattern to heavier card stock to make a final template:
The primary difference between the Valkenburg/Castleford variant that I previous made and the
Mainz is that all of the toe and side straps come together at a single point located about a third of the
way from the front.  The heel straps and ankle straps come together as they did with the other form.

Here is one of the uppers cut out.  Always mark the pattern cutouts on the flesh side in pencil.  To
make the cuts I prefer a #2 xacto blade.  Here I am smoothing the edges of the flesh side using an
Osborn TL-127 #4 edge beveler.  Why round the edges?  That's what the romans did.
Rounding the strap edges
Having finished the preliminary cutting out and edge rounding of the uppers, the next step is to
prepare the backs for stitching.  First oil the leather.  You may skip oiling the outsoles for now.  First
mark the stitch holes every 1/4 inch on a line located about 1/8 inch from the edge.  Then holding the
straight awl at about a 45 degree angle carefully make holes from the grain side through the edge.
Having made the stitch holes, the next step is to stitch the back together.  Here I am using a flexible
needle to make the edge seam.  Some people do this with a needle on each end of the thread, a double
needle stitch.  I achieve identical results by simply going back to the top from the bottom.
The completed back seam ( I only broke through once, no matter, this is all going to get covered up):
The bottom is stitched together using a simple cross-stitch.  Next, the reinforcement strip.  Not only
does it reinforce the back seam the stitches closing the bottom are also protected.  This is a high wear
area and without the reinforcement strip you risk having your caligae come apart.  A simple running
stitch is sufficient here.
Now it is time to stitch on the out-sole.  First mark out where the tunnel stitches are to be located and
trace the outline of the sole on the upper.  Draw a line about 1/8 inch in from the sole edge and make
a mark every 1/4 inch.  Then soak the sole for at least a couple of hours in hot water.  Using the
curved suture needle make the tunnels.  I usually make these about 1/2 inch to 3/4 inches long.  
Attaching the sole to the upper then proceeds as I have shown in the previous drawing, down through
the upper, throught a tunnel, and back up through the upper.  Do this along the entire circumference
of the sole.
With the back done, the sole sitiched on the caliga is ready for nails.
As the shank of the hobnails was a bit too short to be clinched, I went ahead and glued-in the in-sole
before doing the nailing.  For an adhesive I used
Barge Cement.  Draw the nailing pattern in pencil
prior to the actual nailing.  Another change from how I did things previously was to make the out-sole
about 1/8 inch longer than the in-sole.  With the sole extending further back the bulged-out heel look
should be avoided.  Here the finished nail pattern:
The finsihed caliga
The last step is to adjust the length of the straps and touch up on the Neats-foot oil.  This boot may be
laced in a number of ways.  I have simply threaded each of the toe straps on one end of lace so that
they all meet at the same point.  Loop the lace in a zip-zag fashion to bring the heel and ankle straps
together and tie as you would any shoe.
Here are the pair of finished boots.  I decided to double-up the in-sole as the hob nails were a bit long.  
The socks with cut-outs for both the heel and toes come from the Cancelleria Relief.
New construction
Old construction: soles equal length
New construction: sole 1/8 inch longer than in-sole
I recently rebuilt these caligae by replaceing the soles.  Not only is the new sole attached using a layer
to layer tunnel stitch, but I've made the sole 1/8 inch longer in the back.  This should avoid the
bulged-out look that I had been getting when using soles of equal length.

I'm also not sure about wrapping the lace around the tabs.  I've found that it is very difficult to tighten
the lace after wrapping   A simple zip-zag might be the best method after all.
I've just received the book, "Romische lederfunde aus Mainz".  I cannot read it, but it has lots of
pictures of caligae.  Based upon one of the drawings, I relaced the caligae, instead of having all of the
toe straps on one side of the lace I now alternate them on both sides, and made a few more
adjustments to the straps, punching additional holes to shorten the effective length of the straps.  I
managed to remove the large gap that I previously had about the toe:
One more pass at adjusting the toe straps.  I shortened some of them.  This is pretty much the final
form of these boots.
Final form
A word about the lacing.  As far as I know, no caliga has been found in its fully laced form.  We are
forced to perform a bit of speculation here.  The final form of lacing used here is suggested from a
drawing in the Romische Lederfunde aus Mainz book and it certainly works.  Basically they show the
left toe straps laced on the left and the right toe straps laced on the right.  I varied this arrangement a
bit by lacing some of the right toe straps to the left lace and left toe straps to the right lace.  The
opposite lace then passes through the V of the strap.  How I did this was simply a consequence of how
I cut the toe straps.  Bottom line some experimentation is needed to find the best arrangement.

Here is a comparison of the two styles of caligae:
Mainz Caligae
Valkenburg Caligae
Making the Pattern
I've been thinking about what information needs to be provided to make a well fitting pattern for
caligae.  I've concluded that besides the insole outline, which provides a magnification factor for
enlarging the basic pattern, some three dimensional information on the wearer's feet is also needed.  
Sufficient information may be provided by the construction of a duck tape model.  See the
Florentius
site for a description of the process.  Having wrapped your foot in duck tape make two lines, one
showing the back seam and a second showing the top center line where the straps meet:
Carefully cut the duck tape from your foot along the marked lines.  With the duck tape laid flat you
can tell how to adjust the straps.  My insole pattern is shown below.  It is likely best that you make
your own insole pattern.  I have a narrow heel and the pattern has been narrowed to fit me.  Also
remember to make the outsole about 1/8 inch longer than the insole in the back.
My insole pattern
Here is the mock-up after removal from the foot.  Remember to include the insole cardboard as it
helps to keep the shape.
New Mainz Caliga Pattern
Another Pair of Caligae
I just finished a pair of caligae made from my new caliga pattern.  The goal was to produce a pair of
boots more closely resembling
this original boot.

For the first time I managed to make a perfect back seam:
The finished boots:
The nails:
I had a little problem with the thin laces breaking so I replaced them with laces just slightly wider:
After an entire season of use these boots are holding up quite well.  Once again I have replaced the laces with yet stronger
ones.
Yet Another Pair of Caligae
You develop a reputation and people want your stuff, having sold the previous pair of Mainz variant caligae I then proceeded
to make a replacement pair.  The techniques haven't changed so the following pictures serve to fill-in a few gaps.  One thing
that I did change was to cut the out-sole a bit longer than before.  I've discovered that one shoe can be as much as 1/8 inch
longer than the other.  I compensate by cutting the out-sole 1/4 inch, rather than 1/8 inch, longer than the in-sole.

The first step is to lay out the uppers onto the 8oz leather.
I cut the upper using a xacto knife.  In the process of making a pair of caligae, I typically go through 2 to 3 packs of blades.
The next step is to round off the strap edges using an edger:
Before sewing the leather is oiled:
Preparing the backs for the edge seam using a straight awl:
Sewing the edge seam using a flexible beading needle:
A closeup of the bottom seam.  This is a guess.  An alternative is to skive the lower back and fold this over the bottom.
The reinforcement strip is optional. Its application is a good idea as it protects the weakest part of the caliga, the back.  Here
is the pattern that I made for it:
The completed back:
Having completed the uppers it is time to sew on the out-soles.  The next two pictures show this process, down through the
upper, through a tunnel in the out-sole, and back up through the upper:
The next task is the pounding in of the hobnails:
The last step is to adjust the tabs:
Finished caligae: