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Domain and Regency » Government » Aristocratic
An Aristocratic domain is dominated by those who own the land. The term "aristocracy" is derived from the Greek aristokratia, meaning the rule of the best. It perceives itself as a Meritocratic form of government, in which the best come to have the best lands and titles and are thus the best suited to rule. They are also hereditary plutocracies, in that control of the land amounts to a government by the wealthy. However, when land is your primary asset, the ability to control it is often a function of your ability to win wars. When the government is controlled by these privileged men whose military role allowed them to present themselves as the most noble, or best, you have an Aristocracy.
Generally, landed domains are aristocratic, but guilds can be aristocratic when the leading merchants are landed nobles as well. A guild is aristocratic when they are controlled by landed men as money making ventures, to support wars, castle building, and the acquisition of more land and titles. When nobles control a guild, but their interest is not primarily about land and warfare, but simply making money and getting rich, it is more plutocratic than it is aristocratic.
A feudal domain may or may not be aristocratic. Most are, but any system where a regent only directly has the service of his immediate subordinates, and relies on them for the support of their subordinates is a feudal system. Many feudal arrangements are aristocratic.