Part of the Golan was included in the Palestine Mandate.
By Jack Golbert
About the Golan Heights and the “Sacred Principle” as stated tirelessly by the Arab countries, of non-acquisition of territory by war, no one mentions that the June 4, 1967 border includes Israeli territory occupied by Syria in 1948. The Palestine Mandate originally included the Golan Heights.
Well, most of the Golan Heights.
Britain gave the Golan Heights to French Controlled Syria in exchange for French recognition of British control of the oil fields at Mosul in the Mandate of Iraq. The Banias and the eastern shore of the Kinneret are on the Israeli side of the border drawn by the British and the French. The original border did include a finger of land along the southern border of the Golan connecting Syria to a small stretch of the shore of the Kinneret.
It was a thoroughly irrational border but a friend of mine points out that it does indicate a just settlement of the matter. Israel should keep the Golan Heights and give Syria the finger.