The British Mandate over Palestine ended on May 15, 1948, 66 years ago today. As the British withdrew, the Arab armies of Egypt, Syria, Transjordan (now Jordan) and Iraq prepared to enter the territory, transforming what had been a conflict between the Jewish Yishuv and Palestinian Arabs into an international conflict, the first Arab-Israeli War. (Lebanon only participated in border skirmishes.) It is a day Palestinians still mark as Nakba (Catastrophe) Day.
Since, in 1948, May 15 fell on a Saturday, the Jewish Sabbath, the leadership of the Jewish Yishuv declared the independence of the State Israel the previous afternoon, May 14. Further confusing matters is the fact that Israel celebrates its Independence Day (Yom Ha-Atzma'ut), according to the Jewish calendar, on the 5th of Iyar. So given the different calendars, the Israeli celebrations and Palestinian commemoration can fall several weeks apart; Israeli Independence Day fell on May 6 this year.