King of Denmark (1250–1252), Duke of Schleswig, who took the throne after his brother Eric IV was murdered — a killing widely blamed on Abel himself — and fell in battle two years later.
Abel was king of Denmark from 1250 to 1252, a reign of less than two years overshadowed by the crime that opened it. The second son of Valdemar II, he ruled the Duchy of Schleswig and spent years in bitter conflict with his elder brother, King Eric IV Ploughpenny, over power and territory.
In 1250 Eric IV was seized while a guest of Abel, taken out onto the water, and beheaded. Abel swore his innocence with two dozen co-jurors and was elected king, but the suspicion of fratricide clung to him. He fell in battle against the rebellious Frisians in 1252, and the crown passed to his younger brother Christopher rather than to his own sons.
Abel was born in 1218, the second surviving son of the powerful King Valdemar II of Denmark. As a younger son he was granted the Duchy of Schleswig, and through marriage he was drawn into the orbit of the counts of Holstein, ties that made him as much a south-Jutland prince as a Danish royal.
Valdemar II's division of authority among his sons sowed the conflict that defined Abel's life. When his eldest brother became king as Eric IV in 1241, Abel resisted royal attempts to tax and control his duchy, and the two brothers waged a series of destructive wars through the 1240s.
Abel is remembered above all through the shadow of his brother's murder, and the sources — written under the dynasty of the brother who succeeded him — are not kind. They present an ambitious, hard, and grasping prince, jealous of royal authority over his duchy and willing to go to terrible lengths to defend and extend his own power.
The oath of innocence he swore over Eric's death, backed by twenty-four co-jurors, was believed by few then and fewer since; Danish tradition made him a fratricide haunted after death, his ghost said to ride the Schleswig marshes. Whatever the truth, the portrait that survives is of a proud territorial magnate who valued the near-independence of his ducal power above the loyalty owed to a royal brother.
The long feud reached its climax in August 1250. Eric IV, visiting Abel at Schleswig, was seized by the duke's men, rowed out onto the Schlei, and beheaded, his body sunk in the water. Abel at once denied any part in it, cleared himself by a compurgation oath with twenty-four nobles, and was duly elected and crowned king of Denmark.
His short reign was spent trying to secure a monarchy weakened by the scandal and by the concessions he had made to the Church and nobility to win the crown. In 1252 he led a campaign to force the tax-refusing Frisians of the western marshes to submit, and was killed among them — a death that Danish moralists read as divine judgement for his brother's blood.
Abel fell in the marshes near Husum on 29 June 1252. Because his sons were young and abroad, and his name stained, the Danish magnates passed over his line and elected his youngest brother king as Christopher I. Abel's descendants continued as dukes of Schleswig, a lasting source of conflict with the Danish crown.
Abel's brief reign left little but a dark reputation and a dynastic quarrel. The suspicion of fratricide made him a byword in Danish legend, and the exclusion of his sons from the throne, while their ducal line endured in Schleswig, set the stage for generations of strife between the kings of Denmark and the dukes of Schleswig-Holstein. He is remembered less as a ruler than as the central figure of one of medieval Denmark's most notorious crimes.