Jordan (originally called Transjordan) was created out of the Palestine Mandate by Great Britain in 1923, and achieved full independence in 1946. In 1948, during the war against Israel, Transjordan conquered and annexed what became known as the West Bank, including East Jerusalem and the Old City of Jerusalem, but only Britain and Pakistan recognized its sovereignty there.
Though the majority of Jordan’s population is Palestinian or Beduin, since its inception the country has been ruled by the Hashemite clan of Arabia. The Hashemites, said to be descended from the Prophet Mohammed, ruled the Islamic holy city of Mecca from 1201 until 1925, when they were expelled by the al Saud family (which is how Arabia became Saudi Arabia).
From 1953 until his death in 1999 Jordan was led by King Hussein bin Talal, known more commonly as King Hussein. Under King Hussein’s rule Jordan maintained generally close ties with the United States and Great Britain. Though the King’s relations with Egypt’s President Nasser were very poor – Nasser’s intelligence service had tried to assassinate the King multiple times – when the rest of the Arab world lined up behind Nasser’s promises to destroy Israel in May of 1967, King Hussein followed suit.
In a meeting with Nasser on May 30, he was presented with the treaty that Egypt had signed with Syria, placing the Syrian military under an Egyptian general. After quickly skimming the treaty, King Hussein suggested to Nasser “put in Jordan instead of Syria and the matter will be settled.” With his signature King Hussein tied his fate and that of his country to the judgement and wisdom of President Nasser. It was a decision he would quickly come to regret.