Unfortunately, I'm unable to answer your question with regards to Great Britain, whom many would consider the most influential European power for most of the 19th century. I'm simply not informed enough to give you an educated answer to that end. However, I can certainly answer your question with regards to France and Germany.

While there are certainly other precursors to the rise of nationalism, the main turn away from feudal societies and absolute monarchies occurred (mostly) in 1848. In Germany, this meant calls for unification of the small German states. Where and how exactly the talk of unification began is the subject of serious debate. A notable landmark in the process of unification came in a speech given by Johann Gustav Droysen, a Prussian scholar who built a sizable reputation for his study and reverence of Alexander the Great, gave a speech at the Frankfurt Assembly in 1848. In the aforementioned speech, Droysen said, "The German question is not a constitutional question, but a question of power; and the Prussian monarchy is now wholly German, while that of Austria cannot be..."^1 What Droysen is suggesting is a merger between the Kingdom of Prussia and the "nation" of Germany. This concept would evolve slightly between Droysen's speech in 1848 and unification in 1871. In a letter to Prime Minister Otto von Manteuffel, Otto Von Bismarck wrote, I wish only to express my conviction that, in the not too distant future, we shall have to fight for our existence against Austria and that it is not within our power to avoid that, since the course of events in Germany has no other solution."^2 Essentially, Bismarck sees conflict between Austria and Prussia as necessary for German unification. Helmuth von Moltke, a Field Marshall in the Prussian Army, summed up the struggle with Austria as a battle for power and that "Prussia felt itself called upon and strong enough to assume the leadership of the German races."^3 In short, "nationalism" was a rallying call for the unification of Germany. In the end, it worked. Germany would be unified in 1871 and would quickly go on to dispatch France in a short war, much to the humiliation of the Second Empire. Also, if you follow the sonderweg or Shirer theses at all, there are clear examples of that type of logic in these letters and speeches.

As with anything French, nationalism is a bit more complicated than the general narrative that applies to most of Europe. The earliest roots of nationalism can be seen during the French Revolution in the early 1790's. To understand French nationalism, one must truly understand that much of modern French history involves the French Revolution and the founding of the First Republic. The argument goes that most of French political history, at least until the collapse of the Vichy Regime at the end of World War II, centers on the rights gained at the end of the French Revolution in 1793. From the rise of the First Republic until the June Days of 1848, France was controlled by four different regimes (First Republic, First Empire, Bourbon Restoration, July Monarchy). In a real short summary, the First Republic fell because it was too progressive. Napoleon Bonaparte's reign gave rise to a new political ideology commonly referred to as "Bonapartism," an ideology that places emphasis on public order and national glory while somewhat respecting the gains made during the French Revolution. This is the first real evidence of French nationalism in a modern sense. That nationalistic sense was crushed at Waterloo, and despite regaining control of the government for about 100 days, Bonapartism gave way to the Bourbon Restoration in 1814.

The Bourbons were a conservative group of traditionalists ruled first by Louis XVI and then Charles X. The Bourbons sought to go back to a conservative style of rule that was far less progressive than the First Republic and far less involved than the First Empire. It lasted for about sixteen years until Louis-Philippe assumed rule after the July Revolution of 1830. The July Monarchy was nearly as progressive as the First Republic, and in short, the public became increasingly agitated due to their suppression of certain rights gained in 1793 and the socialist nature of some of the July Monarchy policies. Louis-Philippe ordered manufacturing plants to open and hire labor even when no work was done. When these plants closed due to financial crisis, the working class turned on the July Monarchy. Ultimately this paved the way for Bonapartism to return in 1851 under the auspice of one Louis Napoleon.

Think of the Second Empire under Louis Napoleon as the French version of "Make France Great Again." Napoleon III promised to return certain rights and freedoms that had been compromised or eliminated by the July Monarchy, promised a greater European presence, and of course promised greater employment opportunities to the working class. In short, this all was going well until Prussia/Germany invaded in 1870 and humiliated the French in a matter of six weeks.

The Third Republic saw the largest flairs of French nationalism. The foundation of the Third Republic centered on the concept of revanche, or revenge against Germany for the defeat in 1870. Basically, the French people knew a future conflict with Germany was likely, and they eventually wanted to retake Alsace Lorraine and regain their reputation after the humiliation suffered in 1870. When Opportunist-Republicans were able to assume power thanks to the quarrels between Royalists (Orleanists and Legitimists), Bonapartists, Conservatives, and Radicals, those wholly supporting the concept of revanche became disengaged with political discourse and clamored for change. A popular general named Georges Boulanger assumed the role of leader of the reinvigorated revanche movement, and eventually represented radicals, conservatives, and royalists. His reckless nature nearly incited a war against Germany in 1888 during the Schnaebele Affair. Though Boulanger and his movement commonly called Boulangisme died in 1890, the idea of French nationalism and revanche existed until the end of World War I.