Jewish arriving in Palestine until the 19th century came for many different reasons, and many were not successful in establishing their successes in establishing communities varied highly. Judging from historical sources, it cannot be determined if there have been any continuous Jewish community since the 2nd century CE, the time when the Roman Empire introduced radical regulations on Jewish life, thereby causing widespread emigration.
Jewish life continued in Galilee, but until the 7th century, with the Muslim takeover, their existence was under constant threat. Under Muslim rule, Jewish communities and their culture enjoyed safety, but this also became a period of conversion into Islam by an unknown percentage.
Until the 13th century, when communal life in Jerusalem was reestablished and a synagogue opened, there is little information.
From late 13th century, until the middle of the 19th century a period of neglect from distant rulers brought upon Palestine poverty and a decrease in population. This affected the Jews, too, even if there was a century and a half of revival, beginning in the first half of the 16th century: Something resembling a homeland for them was established, and many Jews immigrated from Spain, bringing their part of the population up to 25%.
In the 18th century sources tell that Jerusalem, Hebron, Tiberias and Safed were the main Jewish centres. An official British report from 1864 indicates that Jerusalem had only 15,000 inhabitants, of which 8,000 were Jews. US novelist, Mark Twain, tells in 1867 that Palestine is virtually empty of inhabitants. Estimates for 1880, set the Jewish population at 24,000 in a region with a total of 400,000 inhabitants. There has been much debate about how many actually lived in Palestine in the 19th century, some have stated that today's Arabs in Palestine were immigrants just as much, or more than the case was with the Jews. It is true that there were important waves of Muslim immigration to Palestine in this period, but the mere lack of conclusions tells that we really don't know how many of the non-Jews represented an original population.
In 1922, about 11% of the population in Palestine were Jewish, in real figures they counted ca. 84,000.
In 1931, their number had risen to 175,000, which was 17% of the population.
Fourteen years later, in 1945, the Jews represented 31% of the population, counting more than 550,000.
There is a distinction between those with deep roots, and those whose family history in Israel begins in the early 20th century; Old Yishuv and New Yishuv. Today, the term seems no longer to be in use.