In the tradition of the Germanic monarchy the king had to be elected by a representative assembly of noblemen. Men eligible for election had to be of royal blood; the eldest son of the previous king was not automatically chosen. During the civil war era the unclear succession laws and the practice of power-sharing between several kings simultaneously gave personal conflicts the potential to become full-blown wars. Over the centuries kings consolidated their power and eventually a strict succession law made Norway a principally hereditary kingdom. As a result of the unions with Denmark and Sweden, the heredity principles were several times flouted in the succession to the throne, until they were explicitly abolished in 1450.