West Germanic and Anglo-Saxon kingship
According to Tacitus, power in the Germanic tribes was split between a king and a war-leader (dux in Latin, drihten in the conventionally used Anglo-Saxon).
But this seems to reflect the situation of the tribes fighting Rome in the East more than the norm. That seems to have varied, with the Scandinavians having
relatively little attachment to kingship except for the Ynglingar line in Uppsala, and the West Germanic tribes having a very strong attachment to it.
The Anglo-Saxons are the clearest example of this. Anglo-Saxon kings were also the war-leaders. They are supplied with genealogies going back to Wóden
(except for the East Saxon kings, Seaxnet) and beyond to Jesus and Noah. The king maintained the frith of the entire kingdom; crime and unruliness was an
affront to his majesty.
At the same time, the king was advised by his witan (short for witena gemót, "council of wise men"). The witan signed off on important legislation and
undoubtedly moulded it. It was the witan's duty to guide the king and to check him when he was bent on folly - several kings complained that the witan was
being rough on them. And crucially, the witan selected the king - albeit from the royal family, and albeit almost always choosing the person who would have
been expected by primogeniture. In theory, the witan could also get rid of a bad king. This seems to have happened twice in English history: Sigeberht of
Wessex was deposed in 757 and Alhred of Northumbria in 774. The give and take between king and witan is illustrated by events early in the turbulent 11th
century: in 1013 King Eţelred (the "Unready," a misinterpretation of unrǽd, "ill-advised" or "of poor judgment") fled the country from Sweyn Forkbeard, who
proclaimed himself king. But within a year Sweyn died and the witan called Eţelred back as king - according to the Anglo-Saxon Chronicle, on the condition
that he promise to rule better than he had. Eţelred did so, and was reinstated as king of England.