Radiocarbon Dating of a Spearhead from Kinclaven, Perthshire
14 Nov 2009
The Kinclaven iron spearhead is in the collections of Perth Museum and Art Gallery (registration number: 1991.55)
It was found in the bed of the river Tay close beside Kinclaven castle and was initially identified as a later medieval (13th/14th century) type of spearhead, with an appealing association to be made between the spearhead and the location (the castle was the site of a War of Independence skirmish led by William Wallace). More recently a follow-up look at the spearhead suggested, following typology's including Swanton's, that it could well below a much earlier example of the 6th/7th century. This would make it a useful addition to the small number of early medieval iron spearheads from Scotland (including Scalloway, Shetland; Birsay, Orkney and Dunadd, Argyll).
A notable feature of the spearhead is that its hollow socket preserves a detachable length of the wooden shaft: measuring 95mm long, it tapers to fit neatly in the socket and bears two opposed rivet holes from the rivets which held it in place. Further analysis of this shaft fragment - a radiocarbon determination included - offered clear possibilities for further information.
Anne Crone of AOC Archaeology Group (http://www.aocarchaeology.com/) kindly identified the wood species as ash (Fraxinus excelsior) one of the two commonest woods used for spearheads, the other being hazel. Both are hard, tough, and flexible, and so ideal for use as spear shafts. A small sample of the wood was then supplied to the SUERC (http://www.gla.ac.uk/surrc/) laboratory in East Kilbride, for radiocarbon determination. This was made possible by the giving of a grant to Perth Museum of £290 from the Research Fund of the Society of Antiquaries of Scotland. A rather surprising result came back.
It is shown here on the plot for the 14C date, which came out as 935 +/- 35 BP (that is Before Present, which for radiocarbon calculations is 1950), giving a date of 1045 +/- 35 AD. Of course 14C dates are not so simple as that and with statistical probability we have a 68.2 % chance of the date falling between 1040 AD - 1160 AD and a 95.4% chance of it falling between 1020 AD- 1190 AD.
What this means of course is that we are not dealing with a 6th or 7th century spearhead but an 11th century example, which is, if anything, even rarer. Of course, technically speaking we are dealing with a date for the wooden shaft and not the iron spearhead itself. What we do not know is if the pairing of shaft and spearhead is the original one or a later one due to shaft breakage. Even if we allow some element of inheritance of an heirloom it stretches the bounds of credibility to think that a 6'7th c spearhead was in use/ passed on for something like 500 years. We can perhaps allow that the spear could have been an heirloom over two or three generations but realistically no more. This would give us two basic scenarios to consider, an entirely new spear (head and shaft) of the 11th century or a spearhead (may be as much as a century old) newly shafted in the 11th century.
Mark A Hall
History Officer
Perth Museum & Art Gallery
16 November 2009
