Youth is not always an advantage, though the appearance of youth may be. Vikings, as fighting-men, should ideally be young and fit. Kings on the other hand, should ideally be older and wiser. But the warrior gains authority from experience, while youthful vigour makes for a more effective ruler. The late Viking Age is generally seen as the period when the Scandinavian countries developed a European style of kingship, under the influence of Christianity and continental political theories. But the most notable Scandinavian kings of the eleventh century began their careers as vikings, as roving fighting-men and as the leaders of such men. Having achieved royal power, they often died young, fulfilling the expectations of the proverbial expression that ‘til frægðar skal konung hafa, en ekki til langlífis’ (‘a king is for glory, not for longevity’).

In the medieval Scandinavian laws, the age of majority was normally fifteen. Yet in some Icelandic sagas, the hero is said to have embarked on his first viking voyage or to have otherwise proved his manhood at the age of twelve. This is particularly true of sagas that romanticize their heroes. Thus, in that quintessential viking saga, Jómsvíkinga saga (ch. 21), Vagn Ákason is given a ship and sixty men each by his father and grandfather, and sets out to join the Jomsvikings with a troop in which no man is older than twenty or younger than eighteen, except Vagn himself who is twelve. In the more realistic Gunnlaugs saga ormstungu (ch. 4), the twelve-year-old hero, who is described as precocious and unruly, asks his father to give him a ship so that he might go out and see the world, but his father is less enamoured of the idea and makes him wait until he is eighteen. Elsewhere, the hero is said to have been aged twelve at some other important event in his life. This motif is used a number of times in Laxdoela saga, notably when the twelve-year-old Bolli Bollason avenges the death of his father on his killer Helgi Harðbeinsson (ch. 64).