The Oldest Country

Nation-building is a long evolutionary process, and in most cases, the date of a country's "formation" cannot be objectively determined.

An unambiguous measure is the date of national constitutions; but as constitutions are an entirely modern concept, all formation dates by that criterion are modern or early modern (the oldest constitution being that of San Marino, dating to 1600).

Independence dates for widely recognized states earlier than 1919 should be treated with caution since before the founding of the League of Nations, there was no international body to recognize nationhood, and independence had no meaning beyond mutual recognition of de facto sovereigns.

Many countries have some remote (or fantastically remote) symbolic foundation date as part of their national mythology, sometimes artificially inflating a country's "age" for reasons of nationalism, sometimes merely gesturing at a long and gradual process of the formation of ethnic identity. Such dates reflect not the formation of a state (an independent political entity), but of a nation (an ethnic or cultural grouping), terms that are often conflated in the context of nation-states.