The revolutions of 1848 refer to a series of revolutions that happened in Europe that year and that put an end to the monarchies that were re-established after the defeat of Napoleon Bonaparte in 1815. These were liberal revolutions, meaning that were anti-monarchist, nationalist, and presented the first signals of pro-worker organizations. Examples of the influence of nationalism over these revolutions:
Germany: the German movements that lead the revolution of 1948 were profoundly influenced by the thought of Johann Fichte, a German Philosopher that wrote about German nationalism and called for the political unification of German-speaking people. The main objectives of the revolution were not achieved at the end of it, but the political transformation of Germany that occurred later was compatible with many of these goals.
France: the French revolutionaries were incited by a romantic nationalist spirit that evoked the French past and called for the rebellion of the French workers against the king and the noble. It put an end to the French monarchy and established the Second French Republic.