The first wave came in 638. It was Arab soldiers who invaded and conquered Palestine. Then Crusaders started to gradually squeeze Arabs out. Then came Turks, whose relationships with Arabs were no love lost. They continuedwith the policy of pushing Arabs out, and did it so thoroughly that in 1917, when British enered Palestine, the number of Muslim Arabs there did not exceed 10,000 people.Others were Muslims- but not Arabs.
The second massive wave of Arab immigration to Palestine coincided with the return of Jews who started to create the working places. British, after they got the Mandate for Palestine, speeded this process up, especially when they began to build the sea port in Heifa and to expand the net of the railroads.
Since 1860 to 1948, the Arab population in Jewish Palestine grew from hardly 10,000 to over 1,000,000.