How was Israel established?
At the end of the British mandate on Palestine which gave Israel its legitimacy, Israel was declared an independent state in May 15th, 1948. Answer Israel was established by G-d. Read the Old Testament
If you are talking about the Modern State of Israel, it was established in 1948, and it is still around today. If you are talking about the ancient state of Israel, it was not established "in Palestine". It was established in the Land of Canaan, which later became known as the Land of Israel, and then later called Palestine by the Romans.