Complex sentence: Following the 1948 Arab-Israeli War, Jerusalem was divided into two parts--the western portion, populated primarily by Jews, came under Israeli rule, while the eastern portion, populated mainly by Muslim and Christian Palestinians, came under Jordanian rule.
Split into simpler sentences: Following the 1948 Arab-Israeli War, Jerusalem was divided into two parts. The western portion, populated primarily by Jews, came under Israeli rule, while the eastern portion, populated mainly by Muslim and Christian Palestinians, came under Jordanian rule.