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Conversation with a medieval floor tile

 

Excavation of the Carmelite priory at Lossenham has yielded an interesting collection of pieces of decorated floor tiles; over sixty tile fragments in all. These are presumably the remnants of the original church floor, most of which was taken, or sold, for reuse after the closure of the priory. We have been very fortunate, courtesy of the archaeologists at Isle Heritage [1], to have been able to spend time with these tiles examining them for clues as to how they were made. As so often with ceramics, which can carry the marks of their making through centuries, it is a kind of indirect conversation (albeit a bit one-sided!) with the potter (or tiler) about what was involved in making that particular piece. I'm interested in this conversation because I want to understand how to reproduce the types of tiles found at the site, and the first step is to see what the tile has to say. I should stress that these observations are from the perspective of a potter interested in how the medieval tilers worked; I am neither an archaeologist nor academic expert in medieval tiles.

 

There is a great deal written about medieval floor (and other) tiles, at least from the perspective of what tiles have survived, where they were used, and their design, regional variation and social, religious and cultural significance.  However, as with much else about ceramics of the period, there is little contemporary documentation of the methods and processes used by medieval tilers. When the Victorians became enthusiastic about medieval tile designs the skills of the original tile makers had long since been lost and the production of nineteenth century two-colour tiles, though echoing medieval designs, largely used a different process, well suited to mass production but resulting - to my mind at least - in tiles with a rather sterile, characterless feel. Maybe that's just me?

 

The tile we are looking at here is one of the only tiles from the priory excavations which is more or less complete. This is obviously a great help in making new versions of the tile, both in terms of transcribing the design and accurately establishing the dimensions. But can we pursue the conversation further and find out more about how the tile was made? 

 

To start with, the tile is beautifully flat. Sounds obvious - aren't all tiles flat? - but for anyone who has tried hand-making tiles, it will quickly have become clear that ending up with a flat tile is by no means inevitable. Tiles can warp and arch for various reasons, including the nature of the clay body and how the tile was formed, dried and fired. This tile made it to be part of the church floor, so obviously it was one of the successes from the kiln, however our tiler presumably didn't just get lucky with this one but had developed the right combination of materials and techniques to get consistently flat tiles.

 

What else can the tile tell us? Altough we tend to focus on the design and how it was applied to the tile, it is also useful to take a look at the back and sides of the tile for information about the clay body and the way the tile itself was formed.

Looking at the clay fabric, it is clear (both on the back and front of the tile) that the clay used was pretty rough in terms of inclusion of grit and stones. This was not clay that had been carefully prepared to remove all impurities and make it smooth and even. It would have been tricky clay for throwning on a potter's wheel. It seems likely this was clay simply as it was dug from the ground, roughly mixed and perhaps kneaded by treading to a plastic consistency, grit and all.

 

This is borne out by one thing we do know about tile making practice, at least in the fifteenth century when the tilers' guild set out the following rules:

 

"... the clay therof shulde be diged and caste at Mighelmasse and soo lye open to Cristmas thanne next folowing, and thanne to be turned and caste agen wherby the marle and chalke shulde breke out like as chalkestones and cloddes liying in the frost ar woned to doo. And thanne in the March thanne next ensuying therof shulde be made tyles goode and profitable like as it have been of olde tyme."  [2]

 

In other words, the clay was dug and put into a heap in the autumn, the heap turned and mixed some time after Christmas, and not used for tile making until March. This was put into law by an Act of Parliament in 1477 [3]. The effect of this process would, among other things, have been to mix the clay, to allow the frost action to break up the solid pieces of clay, and to allow moisture to penetrate and even up throughout the heap. However, the clear implication of these rules is that the clay was not processed further, or in other ways, before use. It is inevitable, therefore, that while larger stones and pieces of organic material could have been removed by hand when the clay was being used, the tiles were made including all the smaller grit and other inclusions found when it was dug. The challenge this creates for making the design on the tile face is something we will return to shortly.

 

We might also note that the tile has a bevelled edge - the edge angles inwards from the front to the back. This was common in tiles, presumably to allow cement behind the tile to move into the triangular gap between tiles and bond their edges, while allowing the fronts of the tiles (and hence the pattern) to meet with little, if any, gap.  Forming tiles in this way can be done using a wooden mould with suitably angled inner edges, by cutting the bevel on the edge either after the tile has been made, or by angling the knife if tiles are being cut out of a larger rolled sheet of clay. The latter two seem unlikely to have been used here: given the amount of grit in the clay, any attempt to draw a knife through the clay would almost certainly have dragged grit or stone pieces along, creating horizontal score marks. There are no signs of such score marks along the tile edges.

 

Instead, it looks like the tile was formed by pressing clay into a square mould, with edges sloping inwards towards the bottom (back of the tile). The texture and marks on the sides and back are consistent with this, with cavities and little fold marks where the clay has not completely and uniformly filled the mould space. These marks suggest the clay was relatively stiff when it was used, as softer clay would more readily spread into, and eliminate, such gaps.

 

There is some evidence of embedded sand grains at the surface, suggesting that the the mould sat on a board that was sprinkled with sand before use to stop the clay sticking. There is no evidence of wood grain pattern, so the wood, if wood it was, was well finished.

 

One last thing that is obvious, and slightly unusual about the back of the tile is that does not seem to have any traces of mortar adhering to it, as most used floor tiles do. Perhaps, for some reason mortar was not used when it was laid, or perhaps the mortar did not adhere, or perhaps the tile was never actually used as part of a floor. We will probably never know, but the tile was found outside the church itself, in an area where it seems building materials were collected and sorted, so possibly this tile was one collected for sale or reuse when the floors were taken up. Not having been well cemented down may be why it survived that process more or less intact.

 

Finally, let's turn the tile over and see what the front has to say.

Leaving aside the actual design, what does the tile tell us about how that design might have been applied?

 

The pale pattern is made of a white clay, but is not simply printed, or painted, on to the tile. As with most such floor tiles, the white clay lies in a shallow indented imprint of the pattern on the face of the tile. 

The depth of white clay inlay (illustrated here on a different Lossenham tile)

 

The white clay layer is very thin. It is not simply that the tile has worn down. The remains of the glaze on the white clay layer remain in many places and indicate the original level of the tile surface (see illustration below). There are examples of medieval tiles with rather thicker white clay inlay (2-3mm), but the tiles from the priory site, and many others too, are characterised by the thinness of the white clay pattern (typically 1mm or less), which was clearly deliberate. One possible reason for this is that suitable white clay was uncommon, or possibly laborious to extract, so may have had to be imported (at a cost) from elsewhere, and using it as economically as possible would have made sense. It is also possible that the thinner layer of white clay was more likely to remain bonded to the tile body as both clays underwent shrinkage through drying and firing. Whatever the reason, it required some precise work to produce a clear pattern with such thin inlay.

 

There is general agreement that the patterns were usually created with a wooden stamp, carved with the pattern in relief [4,5]. Evidence for this includes observations (on other tiles) of the imprint of wood grain on the clay under the white slip, where pieces of the white inlay have been lost. What is less clear is how and when the stamp was applied. Suggestions include: the stamp being placed in the bottom of the mould and clay pressed into it, the tile being stamped when newly formed (in the mould or shortly after removal), and the tile being stamped when the 'leather hard'. In any of these cases, the white clay slip (as a paste, or thick liquid) is thought to have been used to fill the indentation (or cover the whole tile), standing proud of the tile so that when it dries and shrinks it still fills the indentation to about the level of the tile surface, with any excess clay being scraped back, once leather hard, to reveal the two colour pattern.[4,5]

 

With the tile here, one or other variant of the processes above seems plausible, but there are also some puzzles. In some areas the surface of the white clay is clearly below the level of the tile face. We can see this is the original surface of the white clay as the glaze remains over much of it.

 

The most likely explanation is that insufficient white clay was used to fill the inlay and as it dried it contracted to below the level of the tile face. Another possible interpretation is that the white clay was stamped into the tile surface with the wooden stamp - a suggestion that has been made - though questioned - in the literature [6,4]. The white clay along the edges of the indentations would seem to support the former view, but it really needs experimental work to test the approaches. 

 

Consideration of the proposed techniques also brings us back to the point raised earlier about the nature of the clay used to make the tile body. Most of the methods assumed to have been used involve letting the clay dry to a leather hard state, and then using some sort of sharp-edged tool to scrape across the surface and remove the excess white clay, creating a flat tile face and sharply defined edges to the pattern. This can certainly be done, but in the latter stages of the process it tends to involve scraping across both the white and red clay. The latter, as already noted, seems to be quite rough and include grit and stones; scraping across such a surface tends to catch and drag bits of grit with it, leaving score marks and sometimes streaking red clay into the white slip. With care, this can be minimised, but it is interesting to note that the tile here, and others from the priory, show no clear evidence of such marks, suggesting there may yet be more to the process than we assume. Again, experimentation may be valuable in assessing the extent to which this was a problem, and possible solutions.

 

So, lastly, to the pattern itself. The tiles were clearly not meant to be seen in isolation, but be combined into groups of four giving the interlocking roundel pattern (below). Whether there were multiple of these quartets next to each other, or whether the groups would be set with different tiles surrounding them (and if so, how the isolated corner parts of the pattern worked) is harder to say; as far as I know there are no extant remains of floors with this tile design set in them.

What has recently come to light is that a single tile of exactly the same design is present in the British Museum collection. That tile came originally from a priory at Lewes, a little over 30 miles from Lossenham. We do not yet know where either tile was made, but comparison of the two tiles (below) would seem to indicate that they were probably stamped from the same woodblock: the similarity of the position of the 'dots' and the petal patterns on the 'flowers' seems closer than might be the case had someone else just copied the general design for a new woodblock. 

Comparison of the two tiles (Lewes tile - grey, Lossenham - colour)

 

Expert analysis of the tiles, currently taking place, may be able to identify the fabric and place of manufacture, and offer other insights. At this stage, however, and from the point of view of reproducing the tile using methods at least close to those used for the original, our conversation has been a useful one. There is much to think about in what tile has had to say, even if it still keeps a few secrets. 

 

Notes

 

1. Thanks to Paul-Samual Armour and Andrew Richardson of Isle Heritage CIC for access to the tiles and for helpful discussions about the context in which the tile was found and other aspects of the archaeology of the site.
2. Green, M (2005) Medieval tile industry at Penn. Records of Buckinghamshire, 45, 115-160

3. Stopford, J (1993) Modes of production among medieval tilers. Medieval Archaeology 37, 93–108

4. Eames, E (1985) English medieval tiles. British Museum Publications, London; Eames E, (1992) English tilers. British Museum Press, London.

5. Van Lemmen, H (2000) Medieval tiles. Shire Publications.

6. Haberley (1937) cited in Hohler, C (1941) Medieval paving tiles in Buckinghamshire - part 1. Records of Buckinghamshire 14, 1–49