in this position until 1015. Eric and Sveinn consolidated their rule by marrying their sister Bergljót to Einarr Þambarskelfir, gaining a valuable advisor and ally. Fagrskinna relates that "there was good peace at this time and very prosperous seasons. The jarls maintained the laws well and were stern in punishing offences." During his rule of Norway, Eric's only serious rival was Erlingr Skjálgsson. Too powerful and cautious to touch but not powerful enough to seek open confrontation he maintained an uneasy peace and alliance with the earls throughout their rule. According to Grettis saga, Eric forbade duelling by law and exiled berserks shortly before his expedition to England. Conquest of England In 1014 or 1015 Eric left Norway and joined Canute the Great for his campaign in England. Judging from Þórðr Kolbeinsson's Eiríksdrápa their fleets met off the English coast (in 1015) but the chronology of the various sources is difficult to reconcile and some scholars prefer placing their meeting in 1014 in Denmark. At that time Canute was young and inexperienced but Eric was "an experienced warrior of tested intelligence and fortune" (Fagrskinna) and, in the opinion of Frank Stenton, "the best adviser that could have been found for a young prince setting out on a career of conquest". The Scandinavian invasion fleet landed at Sandwich in midsummer 1015 where it met little resistance. Canute's forces moved into Wessex and plundered in Dorset, Wiltshire and Somerset. Alderman Eadric Streona assembled an English force of 40 ships and submitted to Canute. The Encomium Emmae is the only English source which gives any information on Eric's actions at this time but its account of his supposed independent raids is vague and does not fit well with other sources. In early 1016, the Scandinavian army moved over the Thames into Mercia, plundering as it went. Prince Edmund attempted to muster an army to resist the invasion but his efforts were not successful and Canute's forces continued unhindered into Northumbria where Uhtred the Bold, earl of Northumbria, was murdered. The great north English earldom was given by Canute to Eric after he had won control of the north. After conquering Northumbria, the invading army turned south again towards London. Before they arrived King Ethelred the Unready died (on 23 April) and Edmund Ironside was chosen king. Following Ethelred's death, the Scandinavian forces besieged London. According to the Encomium Emmae the siege was overseen