What was the rise of nationalism and nation states was most related to?

The rise of nationalism and nation-states was most related to the decline of feudalism and the consolidation of power by centralized governments in the 19th century. This period saw the emergence of shared cultural identities, languages, and histories that fostered a sense of belonging among people. Additionally, the impact of the Enlightenment and the Industrial Revolution contributed to the spread of nationalist ideas, as populations began to seek self-determination and political sovereignty, leading to the formation of modern nation-states.