To inform the consideration of The Inventory of Historic Battlefields in Wales, a phased programme of investigation was undertaken on the battle of Coed Llathan. Detailed reports of these investigations are available and comprise documentary and historical research (Chapman), and non-invasive fieldwork (Archaeology Wales).

Coed Llathan and the related battle of Cymerau took place on 2 June 1257 and marked a significant phase in the extension of the reach and power of Llywelyn ap Gruffudd (d. 1282) as Prince of Wales. Here, an English-led force of knights and predominately Welsh infantry drawn from the Marcher lordships of south and east Wales were defeated by forces led by members of the royal line of Deheubarth.

The Breviate Chronicle provides the following description:

'et apud coeth llatheu anglici omnia uictualia omnes caballos arma et necessaria eorum portantes et omnes palefridos ibidem amiserunt et walense{s} propter hoc leci fuerunt' (Gough-Cooper, b1278.7).

Translation: 'and at the wood of Llanarthne (Coed Llathen) the English lost all their victuals, all their packhorses which were carrying their arms and necessities as well as their palfreys; and the Welsh on account of this were gladdened' (Remfry, 196).

The scale and significance of the defeat of English forces is indicated in the frequency with which details also appear in English chronicles, notably Mathew Paris's Chronica Majora and in a variety of annals maintained in English monasteries, notably Osney and Tewkesbury.

The evidence for the location of Coed Llathen some 5km west of Llandeilo at SN 579 229, as first indicated on the 1st edition ordnance survey map of 1891, is relatively convincing and accords with the chronicle accounts. In this area the Ordnance Survey also note suggestive place names, `Cae Tranc? (Death Field) and `Cae Dial? (Vengence/Revenge field), but whether these are founded on memory or deduction is not clear. None of these names are attested prior to the early editions of the Ordnance Survey (Chapman).

RCAHMW (Battlefields Inventory), Jan 2017

Bibliography
Archaeology Wales, 1257 Battle of Coed Llathen and Cymerau: Battlefield Survey (2014).
Chapman, A., Coed Llathen and Cymerau,2 June 1257: Documentary and Historical Research Report (2013).
Gough-Cooper, Henry (ed.) The Breviate Chronicle: Annales Cambriae, The B Text from London, National Archives, MS E164/1, pp. 2?26, online edition.
Remfry, Paul M. Annales Cambriae: A Translation of Harleian 3859: PRO E. 164/1: Cottonian Domitian, A1: Exeter Cathedral Library MS.3514 and MS Exchequer DB Neath, PRO E. 164/1 (Castle Studies Research, 2007).