Citizenship as a legal institution is governed by numerous international documents as a right but also the duty of every man and citizen._The simplest it can be defined as a legal relationship based between individuals and sovereign state which is by its nature a lasting, based on which certain rights and duties.. That's sufficient to say that there is no country in the world where the issue of citizenship is not regulated by an internal, in many countries and external regulations.. Assumptions for the acquisition and loss of citizenship of each state shall be prescribed arbitrarily, but they must remain within the set framework. Thus citizenship usually acquired on the basis of generally accepted principles of law: l.Principle blood ties or origin (ius sanguinis) 2. Principle areas (ius soli) and 3. Principle residence (ius domicile).Citizenship stops in 3 ways: l.By release 2. Waiver 3. Under international treaties. In Croatia, the citizenship is regulated by the Constitution, international law and, lex specialis, the Law on Croatian citizenship. Some issues related to citizenship can be found in other, primarily administrative regulations and laws.The idea of citizenship first appeared in ancient cities like Athens and Rome, where the citizenship granted to men of a certain class, while the concept of citizenship developed in the era of the great liberal revolutions in the late 18th century and from then until now, this concept is constantly changing and evolving.