Anarchy

When there are two or more powers competing to be the authority in a place, they may produce a zone of lawlessness between their two camps. This is possible because no one can agree about which law to use to solve problems, because everyone cleaves to the law which favors their case. For certain, this kind of anarchy is accompanied by violence between factions, as the only way to settle problems in the absence of law is by force. This situation might be described as civil war if it visits itself on a large enough scale. Otherwise it is probably described as a feud.

Another possible cause of anarchy is a leader who takes no responsibility for the welfare of his people. A ruler who does not wish to be bothered solving the problems of his people, which they cannot settle themselves, is leaving them to feud.

People become accustomed to authority. If everyone expects a certain outcome to a legal issue, even if the authority that once guaranteed such results is gone, that result is pretty likely. At some point however, the especially bold, greedy, or anti-social will defy tradition and test what remains to back up its expectations. When this begins, anarchy has replaced the decline of the old order. It will last as long as no new authority challenges those willing to defy the law. An especially long anarchy can be produced by having this state of affairs followed by Rivals or the Irresponsible Master.
Anarchy is not a happy state. A dying man has no way to pass on his lands to his heirs. There is no way to prevent them from fighting amongst themselves, or from preventing outsiders from simply coming along and taking what was his. Criminals are free to act, because no one restrains them. The strong are a law unto themselves, and may protect their followers, but prey upon everyone else. Force and violence is the only defense against the force and violence of those who would do you harm and take what is yours.
Freedom is a happy state, but it is quite different because transfers of property and other interactions can happen without force or immediate threat of force. This is because there is always some threat of force, but it comes from a distant authority instead of the two parties attempting to interact.