Report number: 69/2017

Title St Giles House and the ‘Riding House’, Wimborne St Giles, Dorset: Scientific Dating and Bayesian Chronological Modelling
Summary An interdisciplinary study involving documentary research and investigation of the fabric of St Giles House was undertaken between 2003 and 2017. The detailed understanding gained has underpinned a detailed programme of repairs and conservation works. As part of a pilot study to determine the feasibility of using luminescence dating of brick to understand historic buildings, 15 bricks were sampled and analysed in 2003–5. In 2014, 15 timbers were sampled for dendrochronology from six areas of the building, and subsequently radiocarbon dating and wiggle-matching was undertaken on two of these cores which could not be dated by dendrochronology. Bayesian chronological modelling was undertaken to combine the scientific dates with the relative and absolute dating of the surviving fabric known from architectural, structural, and documentary evidence. This analysis has clarified the extent of the documented constructed phases. Luminescence dates from the basement show that the east addition of AD 1650–9 incorporated some fragments of an earlier manor house on the site together with some rebuilding. A mid sixteenth-century doorway in this area is reset in a later section of walling. Another luminescence date and the date for a wiggle-matched timber show that this campaign also extended a little further west than previously supposed, including both the north wall and the ceiling beams of what may in the mid-sixteenth century have formed a ground-floor entrance hall. The section containing the putative entrance hall and the great dining room, above, probably slightly predates the AD 1650–9 east addition. Work in AD 1670–4 extended slightly further west and north than thought previously, with works to both the upper brickwork in the Southampton Room being attested by luminescence dating and re-roofing of the Handel Room demonstrated by dendrochronology. Dendrochronology has also shown that the roof over the Southampton Room in the White Hall range was replaced in winter AD 1734/35 or shortly thereafter. Most elements of the surviving fabric that were thought to pre-date AD 1650 have been assigned by the scientific dating and structural phasing to later building campaigns. Luminescence dating and structural phases, however, combine to suggest that the White Hall range was built in AD 1633–1650 (95% probability), probably in AD 1643–1650 (68% probability). Most likely this occurred in AD 1639 or shortly after, when Sir Anthony Ashley-Cooper came of age and took possession of his house from the Court of Wards. A timber dated by radiocarbon wiggle-matching from a lintel over the fireplace in the same area of walling was reused. Eleven timbers from the ‘Riding House’, which was almost certainly built as stables, were also sampled for dendrochronology, those from the roof being successfully dated and yielding felling dates in summer AD 1615 and summer AD 1616.
Series Research Department Reports
Pages 73
  • Bailiff, I K
  • Bayliss, A
  • Bridge, M C
  • Bronk Ramsey, C
  • Cattell, J
  • Dunbar, E
  • Tyers, C
Keywords Dendrochronology ,  Optically Stimulated Luminescence ,  Radiocarbon Dating ,  Standing Building