In 1958, Egypt and Syria formed a sovereign union known as the <answer>United Arab Republic</answer>. The union was short-lived, ending in 1961 when Syria seceded, thus ending the union. During most of its existence, the <answer>United Arab Republic</answer> was also in a loose confederation with North Yemen (or the Mutawakkilite Kingdom of Yemen), known as the United Arab States. In 1959, the All-Palestine Government of the Gaza Strip, an Egyptian client state, was absorbed into the <answer>United Arab Republic</answer> under the pretext of Arab union, and was never restored.
What was the sovereign union with Syria known?
United Arab Republic