The territorial dispute over the land that makes up modern-day Israel and the Palestinian territories is a highly complex issue with deep historical roots going back thousands of years. Both the Jewish and Palestinian Arab populations have longstanding claims and ties to the region.
Some key points about the historical claims:
The Jewish people's ancestral origins and kingdoms trace back over 3,000 years to the Land of Israel, roughly corresponding to the territories of modern Israel/Palestinian areas.
Arabs gradually became the majority population in the region over many centuries under a series of Muslim empires and caliphates after the 7th century CE.
In the late 19th/early 20th century, the World Zionist movement worked to re-establish a Jewish homeland in Palestine, which was then part of the Ottoman Empire.
After World War I, Britain received a mandate over Palestine from the League of Nations and facilitated Jewish immigration, laying seeds for further conflict between Arabs and Jews.
In 1947, the UN voted to partition the remaining British mandate into separate Jewish and Arab states, which the Jews accepted but the Arabs rejected.
In 1948, Israel declared independence, leading to the first Arab-Israeli war as Arab nations sought to prevent Israel's establishment.
So in summary, both populations have very long histories and legitimate ancestral claims to the same territory dating back thousands of years. The modern conflict arises from the question of how to allocate and divide the land between the two peoples. It remains one of the most complex and intractable disputes in the world.