1956 and transferring it to the Suez Canal Authority, intending to finance the dam project using revenue from the canal. On the same day that the canal was nationalised Nasser also closed the Straits of Tiran to all Israeli ships. This led to the Suez Crisis in which the UK, France, and Israel invaded Egypt. According to the pre-agreed war plans under the Protocol of Sèvres, Israel invaded the Sinai Peninsula on 29 October, forcing Egypt to engage them militarily, and allowing the Anglo-French partnership to declare the resultant fighting a threat to stability in the Middle East and enter the war – officially to separate the two forces but in reality to regain the Canal and bring down the Nasser government. To save the British from what he thought was a disastrous action and to stop the war from a possible escalation, Canadian Secretary of State for External Affairs Lester B. Pearson proposed the creation of the first United Nations peacekeeping force to ensure access to the canal for all and an Israeli withdrawal from the Sinai Peninsula. On 4 November 1956, a majority at the United Nations voted for Pearson's peacekeeping resolution, which mandated the UN peacekeepers to stay in Sinai unless both Egypt and Israel agreed to their withdrawal. The United States backed this proposal by putting pressure on the British government through the selling of sterling, which would cause it to depreciate. Britain then called a ceasefire, and later agreed to withdraw its troops by the end of the year. Pearson was later awarded the Nobel Peace Prize. As a result of damage and ships sunk under orders from Nasser the canal was closed until April 1957, when it was cleared with UN assistance. A UN force (UNEF) was established to maintain the free navigability of the canal, and peace in the Sinai Peninsula. Arab–Israeli wars of 1967 and 1973 Prior to the 1967 war, Egypt had repeatedly closed the canal to Israeli shipping as a defensive measure, refusing to open the canal in 1949 and during the 1956 Suez Crisis. Egypt did so despite UN Security Council resolutions from 1949 and 1951 urging it not to, claiming that hostilities had ended with the 1949 armistice agreement. On 16 May 1967, when Nasser ordered the UNEF peacekeeping forces out of the Sinai Peninsula, including the Suez Canal area, Egyptian troops were sent into Sinai to take