المملكة المتوكلية اليمنية
Also in 1958, a Hashemite-led rival, the Arab Federation, was founded between Jordan and Iraq. Tensions with the UAR and the 14 July Revolution made the Arab Federation collapse after only six months. Another attempt, the United Arab States, existed as a confederation between the United Arab Republic and the Mutawakkilite Kingdom of Yemen, but it dissolved in 1961.