The Anglo-Saxon kings built up a set of written laws, issued either as statutes or codes, but these laws were never written down in their entirety and were always supplemented by an extensive oral tradition of customary law. In the early part of the period local assemblies called moots were gathered to apply the laws to particular cases; in the 10th century these were replaced by hundred courts, serving local areas, and shire moots dealing with larger regions of the kingdom. Many churchmen and "thegns" were also given permission by the king to hold their own local courts. The legal system depended on a system of oaths in which the value of different individuals swearing on behalf of the plaintiff or defendant varied according to their social status – the word of a companion of the king, for example, was worth twelve times that of a "churl". If fines were imposed, their size similarly varied accord to the oath-value of the individual. The Anglo-Saxon authorities struggled to deal with the bloodfeuds between families that emerged following violent killings, attempting to use a system of "weregild", a payment of blood money, as a way of providing an alternative to long-running vendettas.