The formation of the French Estates General in the fourteenth century by French King Philip IV led to the rise of the French nation-state. The Estates General was a form of rudimentary representative democracy in which certain members of society were able to influence the political direction of the country.

The French Revolution initially replaced a monarchy with a democratic government founded on universal suffrage; however, this so-called “First Republic” proved ineffective and was quickly replaced by the Directory. The Directory was a group of powerful and wealthy conservative-minded men who replaced the National Assembly and the Convention and began undoing many of the changes wrought by the Revolution.

Prior to the French Revolution, the French parliament was called the Estates General and was formed of three groups: the First Estate, composed of the nobility, which had the most power; the Second Estate, formed of the clergy; and the Third Estate, formed of just about everyone else. The National Assembly grew out of the Third Estate and presided over the initial phases of government during the French Revolution.

The Divine Right of Kings is a political philosophy that justifies or supports Absolutism. It suggests that kings are divinely ordained by God and that therefore to rebel against their authority is to rebel against the will of God. It was widely influential from the sixteenth to the nineteenth century as a legitimizing theory of government for absolutist monarchies from France to Russia. Popular sovereignty says that the only legitimate means of government comes from the approval of the people. As such, it may be understood as the legitimizing political philosophy for Constitutionalism.

The Prince was written in the sixteenth century by the Italian writer and political thinker Niccolo Machiavelli. The book was written as a sort of guiding manual for current and would-be princes. It deals, primarily, with how to acquire and keep power and is famous for the pragmatic and amoral approach that it advocates.

All of these nations were notable nation-states for at least several decades (in some cases several centuries) before the German nation finally achieved unification in 1871. Interestingly, 1871 is also the year many historians point to for Italian unification.

Italian and German unification were both protracted processes that involved the unification of disparate kingdoms, principalities, and republics united only by a shared language and a somewhat-common history. The process began, in both countries, earlier in the nineteenth century, and culminated in 1871. 

During the rise of nationalism in Europe—a process begun around the sixteenth century and culminating in the World Wars of the twentieth century—the most important factor for determining shared national identity was a shared language. This is how German nationality arose from the scatterings of Germanic people around Europe—they often spoke the same root language. The same is true in Italy, France, England, and so on.

Camillo di Cavour was chosen as the Prime Minister of the Kingdom of Piedmont-Sardinia (in Northern Italy) by the King Victor Emmanuel II in 1852. Cavour was a dedicated statesman who used his position to push for economic expansion and, subsequently, the political expansion of his kingdom. By 1871, Italian unification had been achieved.

When trying to answer this question, it is first useful to know what a nation-state is. A state is a political entity, whereas a nation is a cultural or ethnic identity. So, Basque might be a nation in Spain, but Spain is the state that Basque is within. In Europe throughout the late Medieval period, the Renaissance, and the Enlightenment, nation-states began to emerge. Nation-states are political bodies unified with a cultural or ethnic identity. They primarily emerged in countries like England, France, Spain, the Netherlands, and Sweden in the early Renaissance period, and this system of nation-states was then exported around the world as the Western European powers continued to expand their influence. It is now the dominant political entity in the world and its significance has not waned in the twentieth or twenty-first centuries.