The nineteenth-century Ordnance Survey maps still form the basis for much of our understanding of the extent of the linear earthworks that form the Black Pig’s Dyke. The cartographers, (map-makers), working with local people and antiquarians, marked individual stretches of banks and ditches on their maps and annotated them with different (and sometimes interchangeable) names such as the ‘Worm Ditch’, ‘Dunclá’, ‘the Black Pig’s Race’, ‘the Dorsey’ and ‘the Dane’s Cast’.
John O’Donovan
In 1835, John O’Donovan of the Ordnance Survey was the first to suggest that the linear ditches were remnants of an ancient political boundary of Ulster.
The first edition Ordnance Survey maps were marked up according to O’Donovan’s instructions and this provided the basis for all subsequent interpretations of the BPD.
As O’Donovan travelled Ireland he appears to have been responsible for attaching the Black Pig tradition to many sections of linear earthwork which may not have acquired the name in the oral traditions.
William Francis De Vismes Kane
It was the naturalist, and sometime antiquarian, William Francis De Vismes Kane who joined together the earthworks that had been marked by the Ordnance Survey and linked them with ‘the Dorsey’ in Co. Armagh, and the ‘Dane’s Cast’ in Co. Down, to create a grand scheme of shifting earthen walls that defended Ulster against invasion from the south. In 1909 Kane named his creation ‘the Black Pig’s Dyke’.
While Kane’s theories quickly captured the public imagination, they have been criticised as fanciful by many subsequent archaeologists, all of whom have cautioned against joining-the-dots between disparate sections of earthworks that may very well be unrelated. Indeed, only 10% of Kane’s frontiers are made up of bona-fide linear earthworks, plugging the gaps with folk traditions, lakes, mountains and bogs.
Current Research
While much doubt has been cast on the earthworks ever having been an early political demarcation, the alternative speculation has revolved around role as barriers or boundaries that were built to control and/or protect people, cultures and stock. This, or indeed any other use, is yet to be proven.
To find out more about the earthworks, a project was begun in 2014 through the Heritage Offices of the neighbouring counties of Monaghan, Cavan, Longford and Roscommon, with Leitrim joining the project in 2015. The initial phase of the project reviewed the existing archaeological and cultural evidence for the Black Pig’s Dyke and looked towards the future. This report may be downloaded HERE.
In 2015, the project continued to collect empirical evidence for the dating and construction of sections of the earthworks for which there is no existing information, including sites in Cavan and Longford. This will be available to read here in early 2016. It is intended to continue with the project into the coming years.