The Sinai Peninsula has been part of Egypt since the First Dynasty of ancient Egypt (c. 3100 BC). 

In 1956, Egypt prohibited Israeli ships from using the Suez Canal, forcing them to take a much longer route to reach Europe. 

This raised tensions in the region and supported by Britain and France, Israeli forces occupied the Sinai Peninsula. Israel withdrew its troops after pressure from the US and USSR in 1957, with a UN presence established in the region to avoid further conflict. 

In May 1967, the Egyptians forced the UN presence to leave, which led to the Six-Day War that saw Israel once again occupy the entire Sinai Peninsula as well as other territories in the region. 

This initiated a long period of conflict between Egypt and Israel culminating in the Yom Kippur War of October 1973. This conflict proved to be a turning point for both Egypt and Israel and led to a process to find a lasting peace between the two nations. 

The Camp David Accords in 1978 led to Egypt and Israel signing a peace treaty in which Israel agreed to withdraw from the entirety of the Sinai Peninsula. The Israeli withdrawal took place in stages, with the last troops leaving Sinai on April 25th 1982.