'''Arthur's Oven''' or '''O'on''' was a Roman temple which until 1743 stood on rising ground above the north bank of the River Carron not far from the old Carron ironworks. Henry Sinclair, Dean of Glasgow about 1560, calls it 'Arthur's Huif'; and Alexander Gordon speaks of it as 'Arthur's Hoff'. Julius's Hoff is also recorded. Hoff and Huif are Scots for a house or hall. It has been suggested that the name 'Arthur is probably derived from the old Gaelic words Art, a house, and Om, solitary-meaning a retired dwelling or hermitage. The term 'oven' relates to the similarity in shape to the clay bread ovens of the 18th century. In a Charter to Newbattle Abbey (Midlothian) in 1293 a reference is made to ''furnum Arthur'', indicating that it was a well established feature and of unknown origin even at that relatively early date.
A road to Alloa and Airth passed by the back of the Forge Row and through the Stenhouse estate; Arthur's O'on stood on the north-east side of this road. The building was supported by a basement of stones, projecting out from below the lowest course of the building. The marks of three or four steps, which may have formerly led from the ground to the entrance of the building, were visible at one time. The traces of a broad ditch could be seen at one time; suggesting that a regular valum and fosse had once surrounded the building. The O'on was built of dressed stones which were not mortised into each other. In appearance the O'on was shaped like a beehive, being circular on plan with a domed roof. The height, from the bottom to the top of the aperture, was 22 feet. The door was east facing and is said to have had an iron gate, the removal of which by the Monteiths of Cars brought a curse upon the family.
Round the interior of the building there were two string-courses, and in several places, notably over the door, there may have been much weathered carvings in which eagles and the goddess Victory are said to have been represented. A huge stone stood in the interior, possibly an altar or the base of a bronze statue. The O'on may have dated to the period of occupation of the Antonine Wall. The figure of a Roman eagle was at one time been visible, chiselled upon the pavement. Other insignia of the Romans are said to have formerly ornamented its walls, however When Edward I was destroying all important Scottish antiquities, he was only persuaded to spare the 'temple beside Camelon', after the inhabitants destroyed all the Roman sculptures, and inscriptions which existed upon it. The initial letters J. A. M. P. M. P. T., were recorded by Sir Robert Sibbald, engraved on a stone inside the building, under a figure of Victory, with the head and part of the handle of a javelin. The following reading was suggested :- Julius Agricola Magnae Pictatis Monumentumn Posuit Templum. The discovery in a chink of the masonry of a brass finger from a statue, suggested that the O'on was primarily a triumphal monument erected to commemorate a victory. The quality of the structure bears stamp of legionary workmanship, being too elaborate for a purely local masons; and it appears to have been deliberately sited to be visible from the Antonine Wall.
This building was unique in Britain, most likely a temple, being located too far from a fort or road to have been a bathhouse or mausoleum. Its proximity to a spring has resulted in the suggestion that it was dedicated to a Water deity. At the time of its destruction it was one of the best preserved Roman buildings in Britain. A broken carved relief from Rose Hill on Hadrian's Wall depicts Victory, an eagle, and a round domed building under a tree, which may represent a structure like Arthur's O'on. Victory was normally worshipped in the forts, but the best guess is that the O'on was an official monument dedicated to Victory, and also commemorating the campaign, led by Quintus Lollius Urbicus, that led to the establishment of the Antonine Wall.
The structure was tragically demolished to line a mill dam on the River Carron by Sir Michael Bruce of Stenhouse in 1743. The stones however were swept away in a flood the very next day. Several members of the Society of Antiquaries tried to find out the foundation of the building in the 1870s, but without success. Its site, however, was thought to be a few yards to the north-east of the Forge Row, at the corner of an enclosure, about fifty feet square, on the estate of Stenhouse. The ground was then used as a washing-green. The deliberate destruction of Arthur's O'on so appalled Sir John Clerk of Penicuik that in 1763 he decided to have a dovecote built, as an exact replica of the temple, on his estate's stable block. This replica can still be seen today.