There has been a continuous Jewish population in Israel since Biblical times. There have been difficulties maintaining a large Jewish presence in Jerusalem through the millennia -- there was, for example, a bit of unpleasantness with the Romans around the year 70. But Jerusalem has been a majority Jewish city since the 1860s. In 1914, the British estimated that the city contained 45,000 Jews out of a total population of 65,000. When the U.N. partitioned the British Mandate territories into a Jewish and an Arab state in 1947, the Jewish section held 538,000 Jews and 397,000 Arabs. Jerusalem, with its 100,000 Jews, did not count, as the U.N. proposed to make it an international city separate from the Jewish state. As Alan Dershowitz has pointed out, those who claim that Israel was created out of a majority Arab region are counting the Arabs who lived in what was then called Transjordan as well as the West Bank and Gaza.
The U.N. partition plan gave the Arabs more arable land than the Jews and gave the Jewish state a painfully slender nine-mile wasp waist. Nevertheless, the Jews agreed to the partition. The Arabs rejected it and went to war to extirpate the Jewish presence. In the war that followed, Egypt grabbed Gaza and Jordan took the West Bank. There was no talk then of ceding these territories to the "Palestinian" people for a new Arab state. They were merely called Arab refugees and, unlike the equal number of Jewish refugees who fled into Israel from Arab countries, they were denied citizenship, rights, and freedoms by their Arab brethren. They were left to fester in camps overseen by the U.N.
The Jews fled Arab nations because of persecution. Why did the Arabs flee the new Jewish state? (Note, many remained and became citizens of Israel.) Writing in the most recent issue of Commentary, Efraim Karsh reviews some of the new evidence that has come to light about the events of 1948. Not only did the Jews not force the Arabs out of their homes, they made many vain efforts to persuade them to stay put. The 6,000 Arabs of Tiberias, in a typical example, were forced to leave by their own leaders, over strenuous objections from Jewish leaders.
It may be that the local Arabs were urging their people to flee in order to spare them in what they expected would be a genocidal rout of the Jews. Fawzi Qawuqji, a leader of the Arab Liberation Army, vowed to "drive all Jews into the sea." Having tried and failed repeatedly to annihilate the Jews (an ideal the Palestinians have yet to forsake), they labor mightily to discredit the state of Israel, and that, one must sadly reflect, has been wildly successful.