The fundamental principle behind toichology is observation. We can look for consistency in order to determine which portions of a building were constructed at the same time, or we can look for anomalies in order to find breaks in construction and changes in design concept. Usually, common sense will allow us to determine which portions of a building came before or after others, and this in turn allows us to develop a relative chronology. Further study of details and carving styles allows us to narrow the dating of those portions, and in the end we should be able to arrive at a convincing chronology of construction for any given building. On this page we present initial observations and speculate about the likely implications for chronology.

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Project A - Comments Data The data used for the following observations is based on onsite investigations and laser scanning. Implications The underlying images used in this study are from a laser scan made by Andrew Tallon and generously provided to me for research. The original images were high resolution, and they were rescaled by me using Photoshop such that one pixel in the image equals one centimeter. This enabled me to literally measure from the images in Photoshop. This should provide the most accurate measurements possible. These were compared with high resolution zoomable photographs available on this site.

Project A - Royal Portal Plan The Royal Portal was designed for a space 1616cm wide, and the central portal is centered in that space. Implications From the laser scan it was possible to accurately measure all aspects of the portal in elevation. The dimensions proved that the space available was 1616cm between the buttresses of the north and south towers, and that the central portal was centered in the available space. Both of the embrasures flanking the central portal are of the same width (338cm) and both embrasures on the outsides of the side portals are the same width (124cm). The only anomaly is that the left door opening is 195cm, while that on the right is 186cm. Why the 9cm difference? There is a narrow strip between the face of the buttress and the right edge of the embrasure, which is also 9cm wide. It seems very clear - the plinth of this south embrasure was set 9cm too far to the north, and this necessitated a 9cm infill between it and the buttress. How this occurred will be explored below.

Project A - Royal Portal North Embrasure The north embrasure was set 5cm too far to the east. Implications Using guidelines in Photoshop, it was possible to explore alignments between the plinths of the embrasures. Looking closely, one observes that all three of the other embrasures are closely aligned, but it is also clear that the north embrasure is not. Each step in the plinths is set 5cm east of the presumed target. This would be corrected above the imposts, as will be described below.

Project A - Royal Portal North Embrasure There is evidence of cutting back of the buttress of the north tower. Implications The target for the placement of the plinths of the far north embrasure was the face of the north tower buttress (A). The line of cutting is indicated by (B), and (C) represents the edge of the block with the lozenge decoration. The lower part of the buttress was cut back at (D), to allow the stones to be set directly in the same plane as (A). I suggest that (C) was supposed to be in direct contact with (B), but in cutting back the base of the buttress, the masons failed to account for the curved molding of the plinth (F). Further support for this idea is that at (E) the curved molding of the tower was cut down to the level of the top of the second course of plinth of the embrasure (both (E)s are at the same level). I suggest this was to keep the molding of the tower from blocking the view of the lozenge course, and that this lozenge course was supposed to be aligned with (B) rather than (C). So the three courses of the plinth were set against (D), resulting in the entire embrasure being set 5cm to the east of what had been planned. No adjustment could be made because of how the stones of the second course are cut at (F), and how the stones of the lozenge course are cut. The infill stone at (B) was a consequence of these errors, and was never intended.

Project A - Royal Portal North Embrasure The base of the westernmost plinth of the north embrasure is 60cm wide, and the base has been cut back to permit it to be set against the target plane. Implications (A) and (B) represent the setbacks of the base, and the molding at (B) has been cut down to the same level as the bottom of the lozenge course, probably so it would not interfere with it visually.

Project A - Royal Portal North Embrasure The plinth of the north embrasure was unceremoniously chopped away. Implications It appears some effort was made to force the plinth of the north embrasure a little further west, perhaps in recognition of the fact that it had not been set in the proper location.

Project A - Royal Portal South Embrasure The south embrasure is set 9cm too far north and about 5cm too low. Implications On the north side, the base of the north tower buttress has two setbacks. There are also two setbacks at the base of the south tower buttress, (A) and (B). If the erectors believed the situation at the south tower would be the same as at the north tower, they would have cut back through these two setbacks to the plane which they thought represented the target plane, indicated by (C). The lozenge course is set into it in the same way as it is on the north. However, unlike the north tower, the south tower actually has a third setback (D) and the target plane is actually at (E) and not (C). It is 1616cm from (E) to the target plane of the north tower buttress. The difference between (C) and (E) is 9cm. That difference has been made up with a filler at (H) that is not present at the north. The result is that the south embrasure is 9cm too far north, and the doorway it frames is 9cm narrower than its counterpart on the north. The relationship between (F) and the other steps in the plinth seems consistent, but its existence remains unexplained. It appears that at (G) the stone of the tower course has been provided with a turn to meet with the molding of the plinth. This is important because it also appears that the height of the top of the middle course of the plinths of the embrasure was set to match the molding of the tower which, it turns out, is several centimeters lower than the corresponding elevation of the other embrasures. The result was that the entire south embrasure is several centimeters lower than the rest. The correspondence between the height of course (C)/(D) of the tower and the lozenge course of the plinth seems more than coincidental.

Project A - Royal Portal South Embrasure The base of the westernmost plinth of the south embrasure is 60cm wide, just like its counterpart on the north, and the base has been cut back to permit it to be set against what was thought to be the target plane. Implications If, as on the north, two setbacks were cut away, (C) and (D), the 60cm-wide plinth stone could be set just as on the north. However, there is a third setback (E), and it also should have been cut back to permit the right embrasure to be set 9cm further south, so that the doorway it frames would match that on the north.

Project A - Royal Portal South Embrasure The south embrasure is set about 4cm lower than the other three. Implications The reasons for this will be discussed below.

Project A - Royal Portal North Embrasure The north embrasure is the only embrasure that has small column figures beneath the main column figures. Implications This seems to support the conclusion that the north embrasure was the first installed, and was to some degree experimental.

Project A - Royal Portal North Embrasure The decorative colonnettes between the main column figures are composed of shorter segments of more than one length. Implications This strongly suggests that the colonnettes were not made specifically for a specific height, but were made as long as the available piece of stone, and then cut and pieced together to achieve the final height, 358cm. There is no reason to suspect that there was some other planned overall height for this zone of the portals. Each intact colonnette has a band at each end terminating the design. This enabled them to be stacked without concern for continuation of designs. If there was an intent to have them "fit" a particular height, then either all of the colonnettes would be that height, or some combination of two or more segments would equal that target height. In reality, colonnettes are cut to fit the available space without concern for the bands at the ends. This strongly indicates that the colonnettes were seen as "trim", a commodity that came by the centimeter, pieced together and cut to size without any consideration for their original sizes or for any specific designated target height.

Project A - Royal Portal North Embrasure The cutting of the north tower buttress to accommodate the portal is evident to the height of the imposts. Implications The portal sculpture was created to be let into the wall, as is evidenced by the blocking of the lozenge course and also at the capital. The latter protrudes from the wall slightly.

Project A - Royal Portal North Embrasure The blocking on the side of the westernmost capital of the north embrasure protrudes slightly from the wall. Implications From the photo, it is clear that the face of the buttress of the tower is not perfectly vertical. The alignment of each course of the embrasure encouraged a perfectly vertical installation, and that disparity shows up in this detail.

Project A - Royal Portal South Embrasure The westernmost capital of the south embrasure has been carved in a way that takes into account the extra 9cm created by the placement error in the plinths. Implications The figure at the far right sits above the 9cm filler strip. It is not a separate stone from the rest of the capital. This capital was carved with the knowledge of the misalignment, indicating that it was carved after the mistake had been discovered. Comparing this capital with its neighbor, the stone is of a different color and the drapery is quite different, as is the detailing of the canopy. Was this capital remade to account for the placement error?

Project A - Royal Portal Central Piers There are no noteworthy anomalies in the two central piers. Implications Both are the same width, the heights are consistent throughout, they are centered within the 1616cm space, and are set on the same east-west grid as the south embrasure.

Project A - Royal Portal Central Lintel The central lintel sags and has visible cracks in it. Implications There are two obvious cracks in the central lintel. In the center, a crack 3.5cm wide (A) is found at the top, which opens to 6cm at the bottom (D). On the left, another crack 2.5cm wide (B) narrows to being closed at the bottom (C). Open cracks require lateral movement, and the lintel now appears 6cm wider than it was originally, Had there been stonework on either side of this lintel when it cracked, it could not have opened up by 6cm, or in fact, at all. This tells us the lintel cracked before any substantial stonework was installed on either side. This further suggests that the first piece of the superstructure of the Royal Portal to be installed was the central lintel. If we were to take the lintel down, remove the crack filling, and push all the pieces together, it would be the same width as the tympanum above, just as we would expect.

Project A - Royal Portal Central Tympanum The five stones of the central tympanum have shifted with the lintel and do not align properly with each other. Implications The bull and the mandorla stones align properly with each other, but both have sagged with the right piece of the lintel. The lion has sagged with the left piece of the lintel, and its movement relative to the mandorla has caused a 4.5cm gap to open at the bottom between the two stones (A). The upper stones of the mandorla may have been added after the lintel cracked. They both have a proper relationship with the stones beneath them, the eagle on the right also aligning properly with the mandorla. The winged man on the left aligns with the lion below, but because the lion is separated from the mandorla, so too is the winged man (B). None of this movement could have occurred had the archivolts been in place at the time the lintel cracked, further demonstrating that the lintel cracked early on. All of the evidence points to the lintel cracking when the mandorla was inserted between the lion and the bull.

Project A - Royal Portal Central Tympanum The geometry of the tympanum is regular and logical. Implications The base of the mandorla stone is 76cm across, and its corners provide the center points for the arcs of the tympanum, and by extension, the archivolts. The stones of the lion and the bull rise to the midpoint of the mandorla.

Project A - Royal Portal Central Archivolts There is an inconsistency between the voussoirs flanking the lintel and those above the lintel. Implications The curved voussoirs above the lintel are all of the same character, both in the quality of the stone and the style of the carving. The straight voussoirs flanking the lintel are cut from a grayer stone and the figures are in a different style. Despite these differences, the program seems to require these lowest figures. While the angels of the interior archivolt simply continue the host of angels above, the two outer figures on each side bring the total number of Elders of the Apocalypse to the requisite number of 24. These straight voussoirs match the height of the lintel, and were clearly made to do so. Is it possible that the original scheme called for a lintel that was not as tall, a lintel the same height as the rest of the voussoirs (79cm)? An increase in the height of the lintel would have necessitated recarving the straight voussoirs flanking it, or the insertion of short voussoirs at the bottom to make up the difference. More on this below.

Project A - Royal Portal South Portal at Le Mans The South Portal at the Cathedral of Le Mans provides a useful comparison. Implications This portal has a round arch, unlike Chartres, and its lintel is not as tall as that at Chartres. Scholars have recognized the relationships between this portal and that at Chartres, but have consistently placed this portal after Chartres and not before. The lintel and its flanking straight voussoirs are the same height as the rest of the voussoirs. The evidence discussed above and below suggests that the original scheme at Chartres was the same as that at Le Mans, except with pointed arch rather than round. Something encouraged the carver at Chartres to opt for a taller lintel. As it turns out, the lintel at Le Mans also cracked, but it did not spread as at Chartres, perhaps because it was a single portal and the stones flanking the lintel had already been placed and were "locked in". The Chartres carver may have learned of this, and may have decided on a taller lintel to compensate. Even so, it still cracked when the large mandorla stone was placed. More below.

Project A - Royal Portal West Portal at Angers The West Portal at the Cathedral at Angers also provides a useful comparison. Implications Scholars also agree that the West Portal at Angers is closely related to Chartres. Although now missing, the lintel at Angers was also tall, and at Angers now the mandorla is divided into two stones, probably to reduce the weight. All of this points to an evolution of thinking, and the resolution of the problem of lintels cracking under the weight of the centrally-placed mandorla, and it suggests that the sequence began at Le Mans, traveled to Chartres, and then to Angers.

Project A - Royal Portal Left Lower Lintel The left lintel is not as tall as the central portal lintel, and includes unusual subject matter including only ten seated figures. Implications It seems likely that this lintel was cut down from one that was originally somewhat longer. It has all the hallmarks of a Twelve Apostles lintel, including a balding Saint Paul and Saint Peter holding the keys as the two central figures. The central portal lintel was 392cm wide before it cracked, the same width as the base of the central tympanum. It has been suggested above that perhaps it was decided to install a taller lintel, which in turn necessitated taller voussoirs on either side. If the scheme at Le Mans was also the original scheme at Chartres, then any original central lintel would have been the same height as the archivolt voussoirs, or 79cm. The left lower lintel at Chartres is 79cm tall. If this lintel was originally intended for the central portal, and we include the same 14 figures as in the central portal, it would need to be 392cm wide, just like the current central lintel. This would mean that each figure would average 28cm wide. The figures on the left lower lintel average 28cm wide. From all of this it seems reasonable to conclude that the lower left lintel was originally intended to be the central lintel, but was replaced by a more robust version after the issue of cracking at Le Mans became known.

Project A - Royal Portal Left Upper Lintel An adjustment was made to bring the upper zone of the portal into alignment with the facade. Implications It was noted above that the left embrasure was placed 5cm east of its desired location. The magenta lines in the image represent lines parallel to the plane of the faced. The blue lines indicate the offset of the left embrasure and its imposts. The blue line in the center shows the disposition of the lower lintel. The magenta line immediately above it shows the line of the clouds of the upper lintel. From this it can be determined that there is a twist in that upper lintel, shifting from the blue axis to the magenta one. This allowed the stones of the tympanum to be placed on the blue axis, as well as the archivolts.

Project A - Royal Portal Left Upper Lintel The adjustment can be seen in the lintels. Implications The relationship between the lower lintel and the lowest voussoir shows the 5cm offset at (A). This relationship remains at the top of the lower lintel and the bottom of the upper lintel (B). The relationship does not exist at the upper part of the upper lintel (C).