Palestine is a geographical area on the map, it a specific people, government, language, and no they did not live amicably for a thousand years, as tribal wars and conflicts were constant.
Between 1095, when the First Crusade was launched, and 1291, when the Latin Christians were finally expelled from their kingdom in Syria
The Crusades, were organized by European Christians after centuries of Muslim wars of expansion. Their primary objectives were to stop the expansion of Muslim states, to re-claim for Christianity in the Holy Land , and to recapture territories that had formerly been Christian.