United Arab Republic occupation of the Gaza Strip
The United Arab Republic occupation of the Gaza Strip began in 1959 following the dissolution of the All-Palestine Protectorate, which had ruled the Gaza Strip as a client state of Egypt since the 1948 Arab–Israeli War, and its merger with the United Arab Republic. The 1949 Armistice Agreements, which ended the Arab–Israeli War by delineating the Green Line as the armistice line between Israel and its four neighboring countries (Lebanon, Syria, Jordan, and Egypt), left the Kingdom of Egypt in control of a small swath of territory that was part of Mandatory Palestine prior to the war.
Source: Wikipedia — United Arab Republic occupation of the Gaza Strip (CC BY-SA 4.0)