 While his first proposal to invade Denmark fell through, the next year Harald embarked on what would turn into constant warfare against Sweyn, from 1048 almost yearly until 1064.Similar to his campaigns (then together with Sweyn) against Magnus's rule in Denmark, most of his campaigns against Sweyn consisted of swift and violent raids on the Danish coasts.In 1048, he plundered Jutland, and in 1049 he pillaged and burned Hedeby, at the time the most important Danish trade center, and one of the best protected and most populous towns in Scandinavia.