Vetusta Monumenta: Ancient Monuments

Plate LVII: Roman underfloor heating system, recently uncovered at Lincoln.


HYPOCAUSTUM ROMANUM LINCOLNIAE, prope occidentalem Ecclesiae Cathedralis partem sub terra tredecim pedibus anno MDCCXL detectum.
A. Introitus e saxo fabricatus, ubi fornacator ad ignem curandum stetit.
B. Fornax e lateribus arcuatim constructus, igne multum detritus. 
C. Alveus unum et viginti pedes cum quatuor pollicibus longus, octo pedes et quatuor pollices latus, duosque pedes ac quatuor pollices altus; quatuor columnarum lateritiarum ordinibus suffultus.
DE. Bini tubuli duodecim pollices lati, alti vero quatuordecim, ad fumum exhauriendum positi. 
F. Pavimentum tessellatum. 
G. Foramen, ubi operae fodiendo in tubulum E incidentes hypocaustum retegebant.
H. Foramen alterum, ad accuratiorem hypocaustri explorationem apertum.

Inset Plan:
Alvei ichnographia
Alvei sectio.
Scala pedum.

Labels, left to right:
Pillars on the left: 11 pollices/26 pollices; 18 pollices/8 pollices
Middle: pavimentum tessellatum. Caementum 6 pollices altum. 23 pollices. 23 pollices
Right: 19 pollices. 11 pollices. 8 pollices.

Translation (largely quoted from SAL Minutes III.281-82)
Roman Hypocaust at Lincoln, uncovered in the year 1740 near the west side of the Cathedral Church 13 feet under the ground. 
A. The entrance or place where the fornacator [bath-heather] stood to manage the fire, ‘tis built of stone. 
B. The fornax [furnace], built of brick, and arched over with the same, all impaired with fire.   
C. The alveus [hollow floor], 21 feet 4 inches long, 8 feet 4 inches wide, and 2 feet 4 inches high, supported by 4 rows of columns.
DE. Two pipes, 12 inches wide, and 14 inches high, positioned to remove the steam.
F. Tessellated Pavement
G. An opening, where workers incidentally uncovered the hypocaust by digging to pipe E.
H. Another shaft, which was opened to explore the hypocaust accurately.

Inset Plan:
Plan of hollow floor
Section of hollow floor
Scale in feet

Labels, left to right:
Pillars on the left: 11 inches/26 inches; 18 inches/8 inches
Middle: Mosaic floor. Cement 6 inches deep. 23 inches. 23 inches. 
Right: 19 inches. 11 inches. 8 inches.


Engraving by George Vertue after his own drawing of a Roman hypocaust at Lincoln, including some of the equipment used in excavating the monument.  The earliest recorded plan by Thomas Sympson was included in his letter to Browne Willis of 16 February 1740 (NS), communicated by James West at a meeting of the Society of Antiquaries of London (SAL) on 6 March (SAL Minutes III.281-82).  On 13 March Vertue offered to bring a drawing of the hypocaust discovered at Bath in 1727, and received a copy of Sympson’s letter to facilitate the comparison (283); on 20 March he brought the Bath drawing and at the same meeting Cromwell Mortimer exhibited the Royal Society’s wooden model of the hypocaust discovered at Wroxeter in 1701 (Lyster 1707).  Vertue traveled to Lincoln to prepare for this engraving and returned on 8 May with another letter from Sympson and three drawings of his own (SAL Minutes III.298), at least one of which survives and hasd been reproduced in color (Nurse 2007, 127).  The print incorporates material from Sympson’s original letter and plan, as well as all three Vertue drawings, two of which are shown pinned to the wall in this engraved “view of the hypocaust opened,” as the third drawing is termed in the minutes (III.300).  


Roman hypocaust (underfloor heating system often associated with a bath) found beneath the subdeanery near the west side of Lincoln Cathedral and first identified by Thomas Sympson on 10 February 1740.  The structure was discovered thirteen feet underground, and belongs to the only remaining private Roman town house in Lincoln (Wood 2004, 73). 

Commentary by Noah Heringman and Heather Heckman-McKenna

In addition to marking a new departure for Vetusta Monumenta and for the engraver, George Vertue, Roman Hypocaust at Lincoln stands as a landmark in the history of archaeological illustration.  This print is one of the first images anywhere to show a monument in situ during the process of excavation, anticipating the stratigraphic approach of archaeology in the nineteenth century.  From a thematic point of view, this print of the hypocaust—an underfloor heating system commonly used in all parts of the Roman empire—stands out as the largest of the Romano-British monuments depicted during a period (1737-1743) notable for its Roman emphasis: seven of the twenty plates published during this six-year period feature monuments from Roman Britain (1.47, 48, 50-52, 57, 65).  For the first time, Vertue himself traveled from London to another part of the country to document an archaeological find and make his own drawings in preparation for the engraving (which is signed, accordingly, “G. Vertue del & sculp”); the journey to Lincoln would have been roughly four days by coach.  The accidental discovery of the site in 1740 (NS) was quickly made known to the Royal Society and to the nearby Spalding Gentlemen’s Society, which shared several members in common with the Society of Antiquaries of London (SAL).  When the SAL discussed the matter at their meetings that spring and  resolved to send Vertue to document the find, there was already a growing consensus that the Lincoln hypocaust presented a significant new opportunity for understanding daily life in Roman Britain.  

Vertue’s scaled and vividly three-dimensional rendering of the site imaginatively completes the excavation carried out on a much smaller scale by Thomas Sympson (1702-1749), Clerk of the Fabric and Master of the Works at Lincoln Cathedral and an active student of antiquities in the region.  The hypocaust and the room above it were discovered by workmen digging a cellar on private ground adjacent to the cathedral, who struck upon the corner of a vault in February 1740.  The property owner, a Mr. Chanter, informed Sympson immediately and paid for subsequent excavation by him when Sympson realized that this was “an extraordinary antiquity just brought to light” (SAL Minutes III.280).  Vertue’s print, completed the same year, captures something of this excitement.  An assistant described only as a “youth” crawled in via the shaft labeled G on the print to count and measure the forty-four piers supporting the subflooring and “returned like a Chimney sweeper,” the soot on his body confirming Sympson’s educated guess that a heating system had been uncovered (Sympson 1741, 858).  Sympson completed his survey by sinking a second shaft, labeled H on the print, needed to clear the rubble from the furnace (B).  The room above the hypocaust, probably a hot bath (caldarium), actually remained filled with soil, and Vertue only extrapolates the appearance of the tiled floor (F) from a small corner accidentally exposed by the workmen at the bottom of the first shaft (857). 

The hypocaust at Lincoln was not the first to be discovered in Britain, but it was the first such excavation to be supervised by a “practical antiquary,” as antiquaries with experience in fieldwork were sometimes called.  Sympson’s survey therefore added much to what was known about Roman hypocausts in Britain, and Vertue made use of Sympson’s verbal and visual record as well as his own observations to create a holistic vision that integrates the present-day ruin and the labor of excavation with the original appearance of the hypocaust as it could now be imagined. 

In a virtuoso display of the “art of recording” (Smiles 2007, 123), Vertue  faithfully documents the discovery—and the tools used to make it—but creates a wholly imaginary perspective for the viewer.  The imagined viewer—perhaps as tall as the entire excavation, or even a subterranean giant whose head is roughly level with the surface of the ground—seems to stand adjacent to the exposed structure.  A less fanciful interpretation might position the viewer on a gentle slope some distance away from this imaginary pit, but the key point is that this sectional view is richly three-dimensional, making it by far the earliest “of three-dimensional graphics  in British archaeology” (Briggs 2011, 14).  Pinned against the wall of the pit, and transforming it into an architect’s studio, is a more conventional scaled two-dimensional  representation of the hypocaust in plan and section views.  The surface of the ground is also subdivided into two representational registers, with the equipment in the right foreground providing a realistic (if unpeopled) depiction of the excavation work while the model columns and tiles at left and center provide yet another imaginary vantage point for the main structural components of the hypocaust. 

Sympson’s published account helps to make the Lincoln hypocaust one of the best-documented monuments in the series prior to 1744, when explanatory essays began to appear alongside the prints in Vetusta Monumenta.  Sympson addressed his letters on the find to two of the more active fellows of the SAL, Browne Willis (1682-1760) and James West (1703-1772), who also happened to be (like Sympson himself) members of the Spalding Gentlemen’s Society, a regional antiquarian society based near Lincoln (Nichols 1812, vi.114, 119-20).  Extracts from this correspondence were published in the Philosophical Transactions of the Royal Society, accompanied by a more rudimentary engraving based on Sympson’s own drawings as refined by Cromwell Mortimer, another antiquary.  The article includes an account of the excavation, detailed measurements, and some intriguing reflections on the age of the monument.  Sympson briefly reviews existing literature on hypocausts in Britain, also published in the Philosophical Transactions, and addresses Willis explicitly as a member of the Royal Society: “It is of curiosity enough to deserve being mentioned to the Royal Society, I leave it to your care” (SAL Minutes III.282).  West’s decision to have the letter read at the SAL may hint at the gradual drift of this subject matter from the purview of the Royal Society to that of the SAL.  

The latter society’s minutes for the 1730s record numerous discussions of Roman finds.  Responding to the discovery of the Lincoln hypocaust in March of 1740, Vertue exhibited a drawing by Bernard Lens of a part of a Roman hypocaust discovered in Bath in 1727 (SAL Minutes III.286) (This discovery had been overshadowed by the bronze head of Minerva Sulis discovered at the same time and engraved for Vetusta Monumenta in 1730). A letter by William Stukeley on the newly discovered Roman gate at Lincoln was read in 1731 (I.275).  Roman pavements discovered in 1736 and 1737 were published as Vetusta Monumenta plates 1.48 and 1.50-52, respectively.  Two dissertations on this subject—one of them by James West—were read out at meetings in the spring of 1739 (SAL Minutes III.206, 218), not long before the mosaic pavement over the hypocaust was first noticed by the workmen digging at Lincoln.  The sequence of affiliated plates begins with a plan of the Roman roads in Yorkshire (1.47) and ends with another archaeological find, a sculptured gladiator found in Chester and published in 1743 (1.65).  These Roman subjects are interspersed with the more typical medieval monuments, including architecture, coins, and seals.  Vertue’s print of the Lincoln hypocaust is unique, however, in its combination of archaeological and architectural approaches. 

The title of this plate is somewhat underdescriptive of the subject.  First of all, the term hypocaust itself is ambiguous.  According to a definitive work of modern scholarship on Roman baths, even today “there is some uncertainty about the meaning of the term hypocaustus” (Nielsen 1990, 1.161).  Ancient authors use the term in conflicting ways, so it is hardly surprising that there was debate and uncertainty among eighteenth-century antiquaries.  Inge Nielsen’s conclusion that “hypocaust” may be used “as a generic term for the heating system as such” does not depart radically from Sympson’s conclusion in 1740, though she accentuates the distinction between this term and the closely related form hypocausis, which refers exclusively to the furnace and not the whole system.  The Oxford Classical Dictionary points out that “hypocausts were also used for domestic heating in colder lands,” of which Britannia was certainly one (De Laine 2005); the 1887 Encyclopedia Britannica notes that  “in the remains of Roman villas found in Britain the hypocaust is an invariable feature” (“hypocaust, n.”).  The most recent archaeological survey confirms that this site in Lincoln was a Roman villa or townhouse that included a private bath (Wood 2004).  Sympson insisted, correctly, that the heating system consisted of two parts, the furnace (praefornium, called fornax in the print) and the hollow floor supported by piers adjacent to it, but he choose the term alveus (cavity) to designate the latter (Sympson 1741, 859).  Although the term appears in this sense on the print, its customary use is to describe the hot water pools found bordering the main level of the bath (caldarium) itself, as they probably were in this instance.  To confuse matters further, the antiquarian literature on hypocausts assumes that any room above a hypocaust system would have been not a hot water bath but rather a sudatorium or “sweating-room”—which in fact would have been a smaller room located directly above the stove or furnace (Nielsen 1990, 1.159-60).  

Leaving aside these and other problems of terminology that reflect the historiography in this field, it should also be noted that Sympson found a second room with painted plaster walls and additional ducts or tubuli, not to mention early medieval stone coffins several feet above the hypocaust.  The print does not reflect this larger context, but its primary focus on the underfloor heating system seems justified by the completeness of this find, preserved in a high degree of perfection under the main floor of the ruined townhouse.  It seems likely that Vertue’s and Sympson’s meticulous attention to this find helped to inspire the increasing care taken with similar excavations, which bore fruit in 1751 at Benwell (Lewis 2007, 109) and then at Bath, where an entire bathing complex was uncovered in 1755 (Lucas 1756, 222-30 and plate ii).
Sympson’s account details the composition of the hypocaust and comments on the  craftsmanship employed in building it, an emphasis that Vertue extends to the modern craft of excavation in his design.  The majority of the extracts presented from Sympson’s letters refer to his drawings that originally accompanied them, combined into one plate in the Philosophical Transactions publication (Tab. VIII Fig. 1-5).  Three of the figures detail features of the “low Pillars, made of Brick” (Sympson 1741, 856), which are arrayed at the top in Vertue’s print.  Sympson’s key to the letters designating these and other features is essentially an extended prose version of the key included at the bottom of Vertue’s print, and accordingly provides more information than Vertue’s tabular key. The article includes the dimensions of the furnace itself, which Sympson dug the second shaft to ascertain, and describes the foundation beneath the pillars (pilae), not labeled in Vertue’s print, as “a strong Cement composed of Lime, Sand, Brick-dust, &c. which the Masons of that Country call Terrace-mortar” (856).  Sympson’s narrative gives him room not only to distinguish the round pillars around the perimeter from the square ones inside (as we also see in the Vertue print) and to detail the size and quantity of bricks used, but also to declare that  all the pillars “are jointed with mortar, and that very clumsily” (857; Fig. 4C).  The hypocaust is mentioned in an account of the Roman gate at Lincoln by another master mason, James Essex, who compares this “rude but substantial” monument with the hypocaust and argues that the builders’ “little skill in masonry”—together with the uniform elevation of the ground at both sites—constitutes evidence for the monument’s Roman age (Essex 1776, 82-83). 

Sympson situates his investigations in the context of earlier eighteenth-century accounts of hypocausts in the Philosophical Transactions.  The venue was likely chosen by West, who was treasurer of the Royal Society, and who had (as yet) no options for publishing an article under the aegis of the SAL. The development of these venues later in the century may owe something to a growing sense of competition between the two societies (Evans 1956, 100-01) as the SAL began to strive for its own royal charter, finally obtained in 1751.  Sympson’s empiricism is certainly in keeping with the philosophy of the early Royal Society.  His professional bias as a builder coincides with the inductive method in his attention to the lateral course of the tubuli (DE in Vertue’s print), apparently leading to a second room, and in his scrutiny of the rubble that he cleared from the furnace, which included “wood coal” (Sympson 1741, 859).  This is the evidence on which Sympson bases his contribution to the research summarized in the same journal by John Harwood a generation before.  Harwood and his correspondent William Baxter failed to note the impracticality of building a fire in the hollow floor among the pillars, and Sympson establishes his division of the hypocaust system into two parts (fornax and alveus) accordingly.   Harwood himself synthesizes earlier research by Baxter and John Lyster, who had built a model of the hypocaust discovered at Wroxeter in 1701 (860); this model was borrowed from the Royal Society during discussions of the Lincoln hypocaust (SAL Minutes III.285), creating an interplay between two- and three-dimensional representation that culminates in the highly realistic depiction by Vertue.  

The striking absence of any human figures in Vertue’s composition reflects this history of scientific publication, while the realistic details of the excavation mark his innovative response to this tradition.  The use of human figures to indicate scale and suggest mastery in eighteenth-century scientific and technological illustration is well known through examples such as the plates in the Encyclopédie (Ford 2008).  The presence of human figures is the most notable difference between this and a comparable image of excavation, the frontispiece to Sir William Hamilton’s Collection of Engravings from Ancient Vases (1791), a plate dedicated to the SAL.  In the later plate, the figures indicate not only the scale of the operation but also the strong class distinction between the supervising connoisseurs and the workmen digging with their tools. By foregrounding their tools, Vertue’s composition provides a strong hint of the workmen who carried out the excavation.  Their absence may suggest an erasure of the fact that antiquities in the eighteenth century were mainly “unearthed by unsupervised laborers” (Lewis 2007, 110)—a source of both social and methodological anxiety for gentleman antiquaries.  At the same time, this composition leaves room for sympathy with the explicitly professional perspective that Sympson offers when he situates himself and the modern workmen on the same temporal plane as the Roman builders, translating their cement into the English vernacular, “terrace-mortar.”  The care lavished on the pickaxes, shovels, and crowbar (also evident in Vertue’s preparatory drawing) evokes the interdependency of labor and antiquarian research and the walls of the excavation bear the marks of these tools.  The windlass with the buckets suggests an equal-opportunity vehicle for antiquaries, laborers, and rubble. 

By showing the site as abandoned, Vertue also positions the excavators and the builders on the same temporal plane.  In this way, this plate evokes the complex reception history surrounding Roman ruins in the eighteenth century, which must be situated against a backdrop of habitual and controversial comparisons between ancients and moderns. Charles Lucas, the physician who supervised the excavation at Bath in 1755, lamented the depth of modern ignorance about Roman bathing (thus not very discreetly  elevating the importance of the treatise on medicinal bathing in which his archaeological account appeared):
There can hardly be a greater reproach to our nation, than to find a rude, irregular gothic building founded upon the ruins of very magnificent Roman baths and sudatories; which have been celebrated  by the Roman historians, while the noble structures were not only effaced, but their uses become utterly unknown among us. (Lucas 1756, 222)

Bernard Nurse, who rediscovered Vertue’s preparatory drawing for this plate, remarks that Roman remains “were seen as a tangible link between the growing British Empire and that of the Romans” (Nurse 2007, 127).  To partisans of the ancients in Lincolnshire, the discovery of this hypocaust was a point of pride, as indicated in a letter of 1740 by William Warburton: “to shew you we are not quite barbarians in Lincolnshire, I must tell you, that the other day was discovered at Lincoln, 15 feet under ground, a fine Roman Hypocaust” (Nichols 1817, ii.120).  The particular frequency of Roman remains in Lincolnshire was noted early on by Stukeley (SAL Minutes I.65) and the monuments surveyed by Wood (2004) include walls, gates, mosaic pavements, fountains, altars, and an aqueduct, as well as a second hypocaust.  Although Wood includes two photographs of it, the Vetusta Monumenta hypocaust remains “very difficult to access” today (Wood 2004, 2.73), making Vertue’s engraving still a valuable resource for study.    

The Vetusta Monumenta hypocaust stands as a “model example of an underfloor heating system commonly used in Roman buildings in Britain” (Wood 2004, 2:74), an assessment quoted by Nurse in his catalogue entry on Vertue’s drawing, and which might be extended to Vertue’s depiction itself.  Briggs makes a strong priority claim on Vertue’s behalf, arguing that this print “precedes all known three-dimensional images of Neapolitan ruins” (Briggs 2011, 14), including the famous ruins of Herculaneum, rediscovered the preceding year (1738).  On one level this claim restages the competition between British and Roman antiquities that informed the early work of the SAL.  Sympson’s skepticism about the workmanship of the hypocaust, and especially Essex’s related claim that brickwork was known in Britain before the Romans, present an analogous kind of priority claim.  With its uncanny depth of both perspective and excavation, Vertue’s print foregrounds the great equalizer, geology, beautifully captured in Sympson’s affective response to the original discovery: “So deep is old Lindum buried in its Ruins!”

Works Cited

Briggs, C. Stephen. 2011. “Some Notable British Excavations before 1900.” In Great Excavations: Shaping the Archaeological Profession, edited by John Schofield, 12-24. Oxford: Oxbow Books. 

DeLaine, Janet. 2005. "Hypocaust." In The Oxford Classical Dictionary online. Oxford: Oxford University Press.

Evans, Joan. 1956. A History of the Society of Antiquaries. London: The Society. 

Essex, James. 1776. “VII. Remarks on the Antiquity and the Different Modes of Brick and Stone Buildings in England. By Mr. James Essex of Cambridge.” Archaeologia 4: 73-109.

Ford, Rebecca. 2008. “Images of the Earth, Images of Man. The Mineralogical Plates of the ‘Encyclopédie.” In Histoires de la terre: Earth Sciences and French Culture 1740-1940, edited by L. Lyle and D. McCallam, 57-73. Amsterdam: Brill.  

Gaimster, David, and David Starkey, eds. 2007. Making History: Antiquaries in Britain, 1707-2007. London: Royal Academy.

“hypocaust, n.” 2018. OED Online. Oxford: Oxford University Press.

Lewis, Elizabeth. 2007. “Lost and Found.” In Gaimster and Starkey 2007, 109-21.

Lucas, Charles. 1756. An Essay on Waters. Part III. London: Printed for A. Millar.   

Lyster, John. 1707. “A Description of a Roman Sudatory, or Hypocaustum, Found at Wroxeter in Shropshire, Anno 1701.” Philosophical Transactions of the Royal Society of London 25: 2226-27.

Nichols, John. 1817. Illustrations of the Literary History of the Eighteenth Century. Vol II. London: Nichols, Son, and Bentley.

Nichols, John. 1812. Literary Anecdotes of the Eighteenth Century. Vol VI. London: Nichols, Son, and Bentley.

Nielsen, Inge. 1990. Thermae et balnea: The Architecture and Cultural History of Roman Public Baths. 2 vols. Aarhus: Aarhus University Press. 

Nurse, Bernard. 2007. “Excavation of a Roman Hypocaust at Lincoln.” In Gaimster and Starkey 2007, 127 (cat. no. 88).   

Smiles, Sam. 2007. “The Art of Recording.” In Gaimster and Starkey 2007, 123-41.

Society of Antiquaries of London.  1718-. Minutes of the Society’s Proceedings.

Sympson, Thomas. 1741. “XXIX. Extract of Letters from Mr. T. Sympson, to Brown Willis, Esq; Member of the Society of Antiquaries, and to James West, Esq; Member of the Same, and Treas. R, S. by the Publisher, Concerning the Remains of a Roman Hypocaustum or Sweating-room, Discovered Under-Ground at Lincoln, Anno 1739 [OS].” Philosophical Transactions of the Royal Society of London 41: 855-860. 

Wood, Jason. 2004. Conservation Plan for Lincoln’s Roman Monuments. 2 vols. Lincoln: Heritage Consultancy Services.

Further Reading

Cunliffe, Barry. 1971, 1984.  Roman Bath Discovered.  London: Routledge.

Harwood, John, and William Baxter. 1707. “A Letter from Dr John Harwood, LL. D. and F. R. S. to Dr Hans Sloane, R. S. Secr., concerning the Forementioned Hypocaustum. With Part of Two Letters from Mr William Baxter to Dr Harwood, Relating to Wroxeter, and the Hypocausta of the Ancients.” Philosophical Transactions of the Royal Society of London 25: 2228-33.

Zambelli, Alessandro. 2013. “The Undisciplined Drawing.” Buildings 3: 357-379. doi:10.3390/buildings3020357.

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