The lands currently known as Palestine/Israel, Jordan, Iraq, Syria, and Lebanon were regions of the Ottoman empire for some 400 years.
The Ottoman empire ended with, along with internal challenges, its defeat in World War I. France took control of Syria & Lebanon (as a single entity), and Britain of Mesopotamia (Iraq) and Palestine (as separate entities) (Treaty of Sèvres, 1920). Palestine was intended for “the establishment ... of a national home for the Jewish people, ... it being clearly understood that nothing shall be done which may prejudice the civil and religious rights of existing non-Jewish communities in Palestine” (Balfour Declaration, 1917).
Jordan (Transjordan) was established as independent from Iraq, and Lebanon as independent from Syria, all of these countries recognized as increasingly independent through the 1920s and ’30s until the final withdrawal of France and Britain after World War II.
The League of Nations mandate for Palestine (1920) was superseded by the United Nations partition plan (1947) for two independent states, Jewish and Arab. Civil war between Jewish and Arab communities ensued. When the British Mandate expired in 1948, the Jewish state of Israel was declared, and the recently formed (1945) League of Arab States, including Egypt, Jordan, Iraq, and Syria, as well as Lebanon, Saudi Arabia, and Yemen, invaded, resulting in an expansion of Israel (recognized internationally as the 1949 “Green Line” and later the “pre-1967” border) and occupation of the remaining areas meant for an Arab state by Jordan (West Bank) and Egypt (Gaza).
Arab militants continued raids through the 1950s and ’60s, with corresponding responses by Israel.
In 1956, Israel joined Britain and France to attack Egypt in their attempt (which failed) to regain control of the Suez Canal after its nationalization by Egypt. While in Gaza, Israel killed hundreds of Arab militants (or just young men) in Khan Younis and Rafah.
In 1967, Egypt closed the Straits of Tiran (the entrance to the Gulf of Aqaba from the Red Sea) to Israeli shipping, and Israel attacked Egypt (the “Six-Day War”). Jordan and Syria joined with attacks on Israel. Israel captured the Golan Heights from Syria, the West Bank from Jordan, and the Sinai Peninsula and Gaza from Egypt. The Arab League reiterated its policy of no recognition of and no peace or negotiations with Israel.
In 1973 (the “Yom Kippur War”), Egypt attempted to retake the Sinai Peninsula and Syria the Golan Heights. The rest of the Arab League helped them, as did the Soviet Union. Israel pushed them back, but eventually both Israel and Egypt decided to make peace. Israel withdrew back to roughly the Golan Heights as before. With the 1978 Camp David Accords, Israel ceded the Sinai Peninsula and Egypt recognized Israel. Israel annexed the Golan Heights in 1981.
In 2005, Israel removed Jewish settlers and withdrew from the Gaza Strip.
In 2006, the Hamas movement became the elected government for the Arab Palestinians and in 2007 expelled the rival Fatah movement from Gaza. Israel and Egypt put Gaza under blockade. In 2014, Hamas launched attacks on Israel and Israelis, and Israel attacked Gaza to destroy Hamas’s military infrastructure and operations.
Hamas, as well as the Hezbollah movement in Lebanon, continued rocket attacks and incursions against Israel and Israelis.
In 2023, Hamas attacked Israel with thousands of rockets and an invasion by some 2,500 fighters, killing more than 1,400 people and taking more than 200 hostages.