The modern model of statehood (which is probably what you are referring to) -- sometimes referred to as the "nation-state" model, but it is not actually particularly centered on the coextensiveness of the nations and states, and certainly orthogonal to states being ethnonationalist -- is at least ~300 years old (its often attributed to being ~400 years old and originating in the two peace settlements collectively known as the "Peace of Westphalia", but that's not really accurate.) OTOH, the concept of nations (which are basically the coextension of an ethnic community and a land) is much older.

But, in any case, it has not been the case at all that the history of the Levant is one of two local adjacent coexistent ethnonationalist polities, whether or not they look like modern states. That's just a simply false claim made upthread which needs no reference to the history of models of nations or states to rebut; before 1948, for a very long time, the Levant was more often either under one (multinational, imperial) polity or split between a couple of adjacent ones (often in the process of transitioning from unified control of one to the other), whether it was the British Empire, or the Ottoman Empire, a series of different Arab-led empires, the Eastern Roman Empire, the (pre-split) Roman Empire, various Greek-derived empires, the Babylonian and Assyrian empires, etc.