In the beginning of the 20th century, the Jewish population of Ottoman Palestine was between 60,000 and 85,000, two-thirds of them members of the Zionist movement, mostly living in 40 new settlements. They encountered very little violence in the form of feuds and conflict over land and resources with their Arab neighbours or criminal activity. Between 1909 and 1914, this changed, as Arabs killed 12 Jewish settlement guards and Arab nationalism and opposition to the Zionist enterprise increased. In 1911, Arabs attempted to thwart the establishment of a Jewish settlement in the Jezreel Valley, and the dispute resulted in the death of one Arab man and a Jewish guard. The Arabs called the Jews the "new Crusaders", and anti-Zionist rhetoric flourished. Tensions between Arabs and Jews led to violent disturbances on several occasions, notably in 1920, 1921, 1929 and 1936–1939.