Please answer a question about the following article about Germans:

The event of the Protestant Reformation and the politics that ensued has been cited as the origins of German identity that arose in response to the spread of a common German language and literature. Early German national culture was developed through literary and religious figures including Martin Luther, Johann Wolfgang von Goethe and Friedrich Schiller. The concept of a German nation was developed by German philosopher Johann Gottfried Herder. The popularity of German identity arose in the aftermath of the French Revolution.

When did the popularity of the German nation increase?
aftermath of the French Revolution