Final answer:
Britain ruled Palestine until 1948, overseeing a diverse population of primarily Arab inhabitants with Jewish minorities. The 1947 UN partition plan led to conflict, which resulted in the establishment of Israel in 1948 after British withdrawal.
Step-by-step explanation:
The country that ruled Palestine until 1948 was Britain. Under the British Mandate, Palestine included both the region west of the Jordan River as well as Transjordan, the area to the east encompassing the modern country of Jordan. The British took control of the area following the defeat of the Turkish Ottoman Empire in World War I, and their mandate was established by the Versailles Peace Conference of 1919. During British control, the population was primarily Arab and Islamic, with Jewish minorities living along the west coast and in the north, some of them being European Jews who escaped the horrors of the 1930s German oppression.
After World War II, Britain decided to follow the United Nations' proposal, which voted for a partition plan in 1947, splitting Palestine into separate Jewish and Arab states, with an internationally-controlled Jerusalem. Conflict arose between Jewish settlers and Palestinian Arabs, leading to the declaration of the independent state of Israel in 1948, shortly after which neighboring Arab countries went to war against the new state. Despite the opposition, Israel not only maintained its sovereignty but also expanded its territory beyond the U.N. recommended borders for Jewish settlement.