A constitution is a set of fundamental principles or established precedents according to which a state or other organization is governed. These rules together make up, i.e. constitute, what the entity is. When these principles are written down into a single document or set of legal documents, those documents may be said to embody a written constitution; if they are written down in a single comprehensive document, it is said to embody a codified constitution. Constitutions concern different levels of organizations, from sovereign states to companies and unincorporated associations. A treaty which establishes an international organization is also its constitution, in that it would define how that organization is constituted. Within states, a constitution defines the principles upon which the state is based, the procedure in which laws are made and by whom. Some constitutions, especially codified constitutions, also act as limiters of state power, by establishing lines which a state's rulers cannot cross, such as fundamental rights.