The Black Death killed almost everyone settled (ie not a bedouin) in Palestine. This is important because no one can claim their ancestors lived on the land for a really long time. The region which supported million (perhaps even millions) two thousand years ago had less than 150K people around 1400. It won't even double by 1800 and for a good reason: given how arid the region is/was, not tending it constantly made almost all of Palestine into a barren wasteland except a few places like the Valley of Jezreel. It was just a (very) dusty backwater of the Damascus Eyalet of practically zero political importance. That has, of course, changed in more recent history.