On October 6, 1973, Egypt and Syria launched a surprise attack on Israel. They chose this date on purpose. It was Yom Kippur, the holiest day in the Jewish religion. Most Israeli soldiers were at home praying. The attack caught Israel off guard. Egyptian forces crossed the Suez Canal and moved into the Sinai Desert, land that Israel had taken in a previous war. Syrian forces attacked from the north. For the first few days, the advancing armies pushed deep into Israeli territory. Then Israel mobilized its forces and fought back. The war lasted about three weeks. Both sides lost thousands of soldiers. The United States and the Soviet Union each supported different sides. Many people feared the war could spread. Finally, the United Nations helped negotiate a ceasefire. The war had a surprising result. Even though Egypt did not win, its early success gave Egyptian leaders confidence. Five years later, Egyptian President Anwar Sadat and Israeli Prime Minister Menachem Begin signed a peace treaty. It was the first peace deal between Israel and an Arab nation. Sometimes a war can open the door to peace.