Private army

A "private army" is a military force consisting of armed individuals not under the jurisdiction of a nation or state, but who owe their allegiance to a private person, group, or organization.

History
Private armies may form when land owners arm household retainers for the protection of self and property in times of strife and where and when central government is weak. Such private armies existed for example in the Roman Empire following the collapse of central authority and the dynamics at play in such circumstance can be observed in modern day Columbia, on the one hand there are those forces affiliated with the drug cartels, existing to protect their criminality, and on the other those of the landlords created to resist kidnappings and extortion.

In many places these private household retainers evolved into feudal like structures, formalising obligations and allegiances and becoming household troops, and in some cases gaining the strength to allow them to usurp power from or create new states.

Private armies may also form when co-religionists band together to defend themselves from real and perceived persecution and to further their creed, for example the Hussites, Mormon Nauvoo Legion and the Mahdi Army in Iraq; because of their nature such militias are formed by or fall under the influence of charismatic leaders and can become instruments of personal ambition.

Examples

 * Sōhei, the warrior monks of Japan owed their loyalty not to the state or even the Emperor but to their monastries
 * Crusading orders, for example the Knights Templar, Knights Hospitaller and the Teutonic Knights
 * Victual Brothers a pirate brotherhood that for a time became a power in the Baltic
 * The Presidency armies of the British East India Company, and the militaries of the Dutch East India Company, both possessed powerful fleets and created company run states many times the size of their homelands.
 * Atholl Highlanders, Europe's only legal private army.