Nasser's nationalization of the Suez Canal and his emergence as the political victor from the subsequent Suez Crisis substantially elevated his popularity in Egypt and the Arab world. Calls for pan-Arab unity under his leadership increased, culminating with the formation of the United Arab Republic with Syria (1958–1961). In 1962, Nasser began a series of major socialist measures and modernization reforms in Egypt. Despite setbacks to his pan-Arabist cause, by 1963 Nasser's supporters gained power in several Arab countries and he became embroiled in the North Yemen Civil War. He began his second presidential term in March 1965 after his political opponents were banned from running. Following Egypt's defeat by Israel in the 1967 Six-Day War, Nasser resigned, but he returned to office after popular demonstrations called for his reinstatement. By 1968, Nasser had appointed himself prime minister, launched the War of Attrition to regain lost territory, began a process of depoliticizing the military, and issued a set of political liberalization reforms. After the conclusion of the 1970 Arab League summit, Nasser suffered a heart attack and died. His funeral in Cairo drew five million mourners and an outpouring of grief across the Arab world.
Which came later, the United Arab Republic or the North Yemen Civil War?
North Yemen Civil War