The battle of 23 October 1157 in which Valdemar destroyed Sweyn III, eleven weeks after Sweyn had tried to murder him at the Bloodfeast of Roskilde. Sweyn was caught in flight and killed by peasants, ending twenty-six years of Danish civil war and opening the Valdemarian age.
On 23 October 1157 Valdemar, son of the murdered Canute Lavard, beat and killed King Sweyn III on Grathe Heath in central Jutland. It was the last battle of a civil war that had begun with a killing in a wood in 1131 and had run through five reigns, three simultaneous kings and one massacre at a dinner table.
The battle followed directly from that massacre. In July 1157 the three rivals — Sweyn III, Canute V and Valdemar — had agreed to divide Denmark between them and to seal the partition at a feast of reconciliation in Roskilde. On 9 August, at the feast, Sweyn’s men attacked the other two. Canute V was killed outright; Valdemar, wounded, cut his way out and rode for Jutland.
Grathe Heath is therefore not a battle of manoeuvre but a verdict. Jutland rose for the man who had been the victim of a broken oath, and the sources present the outcome as the punishment of treachery. Since the fullest of those sources was written a generation later under the patronage of Valdemar’s closest friend, that framing is worth naming for what it is.
Denmark had been fought over since Magnus the Strong murdered Canute Lavard in 1131 and lost the resulting war at Fotevik in 1134. Eric II was murdered at an assembly in 1137; his nephew Eric III ruled uneasily and then abdicated in 1146, the only medieval Danish king to resign the crown, and entered a monastery at Odense, where he died the following year.
His abdication left no agreed heir and produced two at once. Sweyn, son of Eric II, was elected in Scania and Zealand; Canute, son of Magnus the Strong, was raised up in Jutland. Valdemar, the posthumous son of Canute Lavard, was a boy and became the third party to the quarrel as he grew. The war that followed drew in the German emperor: at Merseburg in 1152 Frederick Barbarossa arbitrated between the claimants and awarded the kingdom to Sweyn, with Zealand to Canute, and it held for barely a year.
By 1157 all three were exhausted, and the partition agreed that summer was an admission that none could win: Sweyn took Scania, Canute Zealand, Valdemar Jutland. It was to be confirmed at Roskilde over dinner.
The feast was held on 9 August 1157. According to the account Saxo Grammaticus set down about forty years later, Sweyn had planned the attack in advance; the lights were put out and armed men came in. Canute V was cut down where he sat. Valdemar took a wound to the thigh and fought his way to the door with Absalon, his foster-brother, and got clear of the town.
The political effect was immediate and total. A killing at a feast of reconciliation, under oath and under a roof where guests had been received, broke the one rule that made negotiated settlements possible in a war of this kind. Men who had accepted Sweyn as king were released from the reasons they had for doing so.
Valdemar reached Jutland, had his wound treated and raised the province. Sweyn had to follow him: leaving a wounded claimant in possession of Jutland with a fresh grievance was not a settlement he could live with.
The armies met on Grathe Heath, open ground in central Jutland beside Hauge Sø, north of what is now Thorning. Sweyn had brought his forces from Zealand and Scania into a province that had gone over to his enemy, and the fighting was short. His army broke and ran.
Sweyn did not get away. He was caught in the wet ground during the flight and killed by local peasants — the detail on which the Danish sources agree and dwell, because a king of Denmark being knocked off a bogged horse and killed by farmers made the point about broken oaths better than any sentence could. He was about thirty-two.
No source gives the size of either army, and none describes the fighting as a sequence of events. What survives is the shape of the day and its ending, which is characteristic of Danish battle-writing in this century: the annals record who died and the chronicles record what it meant.
Valdemar was now sole king at about twenty-six, and he reigned until 1182. The partner in the reign was Absalon, the foster-brother who had got him out of Roskilde: bishop of Roskilde from 1158, archbishop of Lund from 1178, and the man who fortified the fishing village of Havn that became Copenhagen.
Together they turned a kingdom that had spent a generation fighting itself outward against the Wends of the southern Baltic. The temple-fortress at Arkona on Rügen fell in 1168 and its idol of Svantevit was pulled down, which ended the Wendish raiding that had made the Danish coasts unsafe and gave the crown a run of profitable campaigns to bind its magnates to.
The dynasty was secured with the same care. In 1170 at Ringsted, Valdemar had his father Canute Lavard canonised and his own seven-year-old son crowned co-king on the same day — a single ceremony that made the murdered duke a saint, the murdered duke’s descendants the rightful line, and hereditary succession the rule. That son succeeded as Cnut VI without a fight, which in Denmark was the novelty.
Sweyn was buried at Grathe, and a chapel was raised on the heath where he fell; its foundations are still traceable and are marked out on the ground today. The byname the sources give him — Sweyn Grathe — is taken from the place he lost, which is an unusual way for a king to be remembered and tells its own story about who wrote the record.
That record is overwhelmingly one work. Saxo Grammaticus wrote the Gesta Danorum at Absalon’s urging and largely on Absalon’s information, and Absalon was standing beside Valdemar at the feast and through the campaign. Saxo is detailed, vivid and hostile to Sweyn, and there is no surviving account from Sweyn’s side to set against him. The short Danish annals confirm the dates and the deaths and nothing else.
What can be checked holds. The Roskilde killing of Canute V, the date of the battle and Sweyn’s death on the field are recorded independently of Saxo in the annal tradition. The reported dialogue, the treachery foreseen and the moralised ending are Saxo’s, and belong to the literature of the Valdemarian court rather than to the evidence for 23 October 1157.