Abel , King of Denmark Abel of Denmark ( 1218 – 29 June 1252 ) was Duke of Schleswig from 1232 to 1252 and King of Denmark from 1250 until his death in 1252 . He was the son of Valdemar II by his second wife , Berengária of Portugal , and brother to Eric IV and Christopher I . As Duke of Schleswig , Abel came into conflict with his brother , King Eric IV , whose murder in 1250 he was suspected of orchestrating . Upon taking an oath to clear himself of the allegations , he was elected king . After a short reign , he was killed during a military expedition in Frisia . Abel ' s reign was the shortest of any Danish monarch since the 9th century . He founded a line of Dukes of Schleswig - the " Abel family " - which ruled the Duchy of Schleswig until 1375 . Early life . At the election in 1232 of his elder brother Eric as their father King Valdemar II ' s coruler and heir , Abel was chosen to succeed Eric in his position as Duke of Schleswig . In 1237 he married Matilda of Holstein , a daughter of Adolf IV , Count of Holstein . As Count Adolf withdrew to a Franciscan friary the same year , Abel spent several years acting as regent for his under age brothers - in - law , John and Gerhard . Duke of Schleswig . At the death of Valdemar II in 1241 , Duke Abel ' s brother Eric acceded to the throne of Denmark as Eric IV . The following years Duke Abel fought against his brother , trying to gain independence for the Duchy of Schleswig . He raided north as far as Randers , ravaging Eric ' s supporters and then moved into Funen . Eric struck back a year later surprising Abel ' s garrison at Schleswig , forcing Abel ' s young daughter Sophie to flee " without so much as a pair of shoes for her feet . " The fighting continued until Abel ' s sister Sophie of Brandenburg brokered a truce between Duke Abel and King Eric that held until 1250 when Eric was murdered while a guest at Duke Abel ' s residence at Schleswig . King . Eric IV was slain by Abel ' s chamberlain , Lave Gudmundsen and others ; the king ' s headless body dumped into the Schlei . Even though Abel and twenty - four noblemen swore an official oath ( " dual dozen ' s oath " , in Danish " " dobbelt tolvter - ed " " ) that the Duke had no part in the killing , it was widely believed that King Eric was murdered at his brother ' s bidding . " Abel by name , Cain by his deeds " ( Danish , " " Abel af navn , Kain af gavn " " ) , or so people said . After clearing himself of the allegations taking the oath , Abel was proclaimed King of Denmark at the Viborg Assembly ( Danish : landsting ) on 1 November 1250 . Death . Abel only ruled for a year and a half . King Abel received word that the peasants in Frisia , led by Sicko Sjaerdema , refused to pay the tax levy . Abel raised an army to punish them . At the age of 33 , he was killed by a wheelwright named Henner on Husum Bridge near Eiderstedt on 29 June 1252 . At the time , Abel ' s half - grown son Valdemar was held for ransom by the Archbishop of Cologne , and so Abel ' s youngest brother Christopher I , was crowned King on Christmas Day 1252 in Lund Cathedral . After her husband ' s death , Queen Matilda entered a convent but later left it again . In 1261 she married Birger Jarl of Sweden . Legacy . Most people at the time viewed Abel ' s sudden death as God ' s judgment on him for the murder of his brother . As Abel ' s body lay in Schleswig Cathedral , the monks heard strange sounds in the church at night . They said they were too afraid to go into the church after that . They believed that Abel ' s unholy ghost walked abroad at night . Consequently , the kings body was taken outside the church and stuffed into a soggy grave near Gottorp Castle outside Schleswig . Someone rammed a wooden stake through Abel ' s chest to make sure he remained in his grave . It was said long after that the king ' s ghost found no peace and from time time there were reports of " Abel ' s wild hunt " where a black faced man on a white horse and glowing hounds hunted across the moors and forest of Schleswig . Abel ' s descendants — the " Abel Family " — ruled South Jutland until 1375 , often in co - operation with their relatives in Holstein , and they created a permanent problem for the Danish government . Their rule meant the eventual separation of Frisia , Holstein , and most of Schleswig from the rest of Denmark . Marriage and issue . With his wife , Mechtild of Holstein , whom he married on 25 April 1237 ;