"Nationalism is a modern movement. Throughout history people have been attached to their native soil, to the traditions of their parents, and to established territorial authorities; but it was not until the end of the 18th century that nationalism began to be a generally recognized sentiment molding public and private life and one of the great, if not the greatest, single determining factors of modern history. ..the American and French revolutions may be regarded as its first powerful manifestations. "

https://www.britannica.com/topic/nationalism