I think most Americans are under the impression that most of the Middle East has been at war for as long as anyone can remember, but is that true? I used Israel in the title because it is a relatively young country, but most of the countries there are almost the same age (or at least they have undergone a drastic restructuring in the last 100 years). So what was this area of the world like before, say, 1900?
The region has a long, long history of being in the crossroads of Empires andbeing conquered over and over again. People have been massacred, purged, forced into exile, replaced, subjected, forced into slavery and so on over and over and over again.
The Persians allowed the Jews displaced by the Assyrians and Babylonians to return to Israel, where they were allowed a large amount of religious autonomy to worship as they pleased.
The Macedonians under Alexander the Great conquered the Persian Empire, including the Levant and Israel. At the death of Alexander, the region came under the rule of the Selucid Empire, who fought Ptolemaic Egypt (both were Macedonian Generals who carved out their own mixed Hellene and Oriental Empires from the remains of Alexander's conquests).
As the Selucid Empire declined, the semi-Hellenized Hasmonean Kingdom, encompassing Israel emerged as a fully independent state., Later, it became a Roman client state, and after several revolts against Roman rule, the Romans ended the state and merged it with one of their provinces.
I have seen it argued wether or not all the Jews were expelled after the last revolt against Rome, or if just the political, economical and religious elite were. Some genetic studies made in Israel suggest te latter.
The region remained part of the Rome (and then the Eastern Roman Empire), although fought over between the Romans and Parthians (and later Sassanids) until conquered by the Arabs during the 630s.
Source on the genetic studies suggesting that the Palestinians are mostly descended from Jews who remained and converted to islam during the Arab conquest.
The region continued to be ruled by various Arab rulers until the Crusades, when it briefly (in the big scope of things) came under the Control of several Christian states, including the Kingdom of Jerusalem. Then the region came under the rule of Mameluke Egypt, who ruled it until the Ottoman Empire 1517. It was ruled by the Ottomans until captured by the British in 1917.
By then, the Jewish diaspora had already started to turn to their own brand of nationalism - sionism - and were moving to Israel in an attempt to get back to their origin and form a Jewish state there - which they succeeded at in 1948.