Canute the Great (Knútur riki), the ruler both of England and Denmark, "Sovereign of five Realm" as he is styled in the old British chronicles, once went to Southern Sweden—then Danish—to suppress a rebellion, which had been incited by his son Hardicanute (Hörðaknútur) and by Úlf Jarl (Úlfur jarl, or Earl Wolf), a powerful chieftain and courtier.  Rumors of the advance of the royal fleet having reached them, these latter deserted their followers and allies, among whom were the kings of Sweden and Norway, and hastened to make their peace with the monarch.  The fleet sailed into the mouth of Helga river (Icelandic, ain helga = the holy river), where a fierce battle ensued.  The Anglo-Danish King's own ship was at one time in imminent danger, but Úlf Jarl, at great personal hazard, succeeded in saving it.  Canute now went to Roskilde, the capital of his Danish domains, where he arrived the day before the feast of St. Michael in the year 1027.  Here Úlf Jarl, eager to wipe out his former offence, welcomed him with a splendid banquet, and endeavored, by merry words and submissive speeches, to reinstate himself in Canute's graces.  But all his efforts to please the incensed monarch were futile; the latter continued to look grave and ill-natured.  In the course of the evening the Jarl challenged his sovereign to a game of chess, and the challenge was accepted.  During the game, Canute made a hasty move and left a knight en prise; the Jarl captured it, but the King requested him to replace it, and either make another move, or else allow him (Canute) to recall his former move.  The Jarl refused, arose from the table in anger, overturned the pieces, and walked away.  The King, with a bitter laugh, called to him and said:—"Are you running away, you cowardly Wolf!"  The Jarl turned and replied:—"You would have run much farther away at the Helga river, if you had been able.  You didn't call me a coward then, when I came to your help, while the Swedes were slaying your men like dogs."  The next morning the pious sovereign, who rebuked his irreverent courtiers by the sea-side with such religious philosophy, and who had just returned from an humble pilgrimage to Rome, sent one of his Norwegian men-at-arms to the church in Roskilde, in which the poor Jarl had taken sanctuary, and had him slain in the choir.  This adds another to the singular parallels of history, for Úlf Jarl appears to have been to Canute the Great what Thomas-a-Becket was to Henry the Second. (Chess in Iceland and in Icelandic Literature, Fiske, 1905).