‘Is it the end of the world?’ asked one thirteenth-century Welsh poet, when English forces stormed into Wales in 1277. The key instigator was King Edward I, whose campaigns of 1277-1307 were fundamental for how Scottish, Welsh and English people identified themselves. By mapping Edward’s movements, we can investigate how he promoted a singular British national identity, a Rex Britanniae, provoking consideration over how debates regarding sovereignty and self-belonging in the thirteenth-fourteenth centuries are remarkably similar to those of the twenty-first century – calls for Scottish and Welsh independence are certainly no novelty.
A key element of Edward’s approach to kingship was Arthurianism, particularly for Wales. Taking advantage of a popular thirteenth-century obsession, Edward saw himself as the mythical king’s successor.  That he and Queen Eleanor attended the reinternment of the bones of ‘Arthur’ and ‘Guinevere’ just months after defeating the Welsh is non-coincidental. Whatever its plausibility, this was symbolic, a truly political performance; Edward sought to embody Arthur as legitimate overlord of Wales.
Yet ideological mastery was insufficient. Magnificent castles such as Beaumaris and Harlech were catalysts for Anglicisation, visually documenting the physical and metaphorical permanence of English conquest.  As Map 1 shows, these castles were also strategically significant – Rhuddlan as an army base, Caernarfon as a supply centre. The administrative role of castles – the castle boroughs – was the machinery behind Rex Britanniae. Realised through the Statute of Wales (Rhuddlan Castle, 1284) explicitly English administrative cadre were imprinted onto boroughs.
Often called ‘Anglicisation from above’, ‘the first colonial institution’, the Statute never aimed to create unity between English and Welsh law.  It represented the tenacity of Edward’s Arthurian ‘United Kingdom’ ideology and the battle over sovereignty, climaxing in large-scale, coordinated attacks on Edwardian castles, namely in 1294. 
While Wales had no single ruler and yet was relatively ethnically homogenous, Scotland was politically united under the Scottish kings, despite being a melting pot of Brittonic, Gaelic and Viking elements, further complicated by the English-speaking population inhabiting South-Eastern Scotland.  Yet the division between England and Scotland was primarily not cultural but political, and fluid, made remarkably clear in Map 2. Here, a tiny Scotland is presented as a “land beyond the sea”, connected to an English mainland only by Stirling bridge.
Map 2 – Matthew Paris’ Map of Britain, (c. 1250).
Yet no bridge would stop Edward. Arthurianism was most powerful regarding Wales, but it was certainly not irrelevant for Scotland – a multiplicity of Arthurian myths existed. The hereditary right of Arthur’s successors to rule Britain in its entirety was central to Arthurian territorial ideologies. Viewing the Anglo-Scottish border as a purely internal division, Edward used this ideology to try to absorb Scotland, like Wales, into the inalienable royal fisc – the Crown’s taxation and revenue source.
Castles were again essential in realising this and the castles of Scotland and Northern England became key battlegrounds between these two realms. Tensions escalated from 1290, partly over Edward’s determination that all royal fortresses come under his custody. What was for Edward a logical step ensuring Scotland’s security was a denial of sovereignty for the Scots. These castles were the ‘instruments of raw power’, whose loss was catastrophic. 
The border-lands saw some of the most vicious attempts to subdue Scotland: for example, the 1296 bloodbath, the Battle of Berwick. Edward had captured the castle, massacred its townspeople, and garrisoned the fortress – so, what did this mean for Rex Britanniae? Tensions with Scotland’s heir John Balliol were already fraught, but Edward’s actions, combined with the withdrawal of his support for Balliol’s claim to the Scottish throne, resulted in Balliol’s formal renunciation of his oath to Edward.
Map 3 – Edward I’s Scottish campaigns. Note the importance of the border-lands as key entry, exit and fortification points. Copyright @Charlotte Tomkins
Berwick was a watershed moment, where Balliol confronted the hard truth – his enthronement was only ever temporary; where Rex Britanniae was performed and destroyed as Edward gambled with Balliol’s loyalty for the motive of reducing Scotland to a vassal-state of England.  Revolts from 1296 – which Map 3 shows Edward’s efforts to put down – simply demonstrate that a shared Scottish identity was being strengthened. 
The King in Motion
Edward’s attempts to realise a Rex Britanniae depended on impregnable, looming castles – but it also depended on almost ceaseless movement. These campaigns can be drawn on conventional static maps. But by plotting his known locations and dynamically projecting them onto a map we can see – for the first time – the rhythm of Edward’s movements and their consequences, watching as he gathers forces and builds a consensus in England, before striking north and west.
Map 4: click to access moving images and all data
Viewing Edward’s reign in this innovative way allows us to not only visualise his efforts to become the rex Britannie, but also to begin to quantify his movements, highlighting the importance of warfare and conquest throughout Edward’s reign. The statistics below elaborate on the movements in Map 4 :
Figure 1 – During peacetime years alone Edward spent 116 days in Berwick-upon-Tweed, surpassed only by Windsor (157) and Westminster (956), delineating its strategic, ideological and political importance. (J. E. Crockford, ‘The Itinerary of Edward I of England: Pleasure, Piety and Governance’ (Turnhout, 2016), p. 245.)
Edward’s death in 1307 made hopes of achieving Arthur’s united Britain impossible. Edward’s success was not linear; while the Anglicisation of Wales was long-lasting, the Scottish conquest ultimately failed. What we can say, however, is that Edward’s ideology of a United Kingdom still remained influential even after his death; even now people are still debating the very concept.
Charlotte Tomkins is in her final year of an undergraduate history degree at the University of Sheffield, with ambitions to continue the subject at MA and PhD level. She recently completed the Sheffield University Research Experience (SURE) where she examined the links between the itinerary of Edward I and his pursuit of a single kingdom, a Great Britain and a United Kingdom, under his kingship, using databases and cartography. She focused on how castles were at the heart of Edward’s vision, and how debates over British national identity are not contemporary; they have been heated since the medieval period and earlier.
 D. Jones, The Plantagenets: The Kings Who Made England (London, 2012), p 98.
 R. R. Davies, ‘Edward I and Wales’ in T. Herbert and G. E. Jones (eds), Edward I and Wales (Cardiff, 1988), p. 1.
 Ibid., p. 2.; Jones, The Plantagenets, p. 314.; M. Prestwich, Edward I (London, 1988), pp. 205-206.
 M. Morris, Castle: A History of the Buildings that shaped Medieval Britain (London, 2012), p. 134.
 M. Morris, Edward I: A Great and Terrible King (London, 2009), p. 241.
 Ibid., pp. 236-237.
 P. Parker, History of Britain in Maps (Glasgow, 2017), p. 26.
 P. Traquair, Freedom’s Sword: Scotland’s Wars of Independence (London, 1998), p. 13.