of Moharram one thousand three hundred and thirty nine Hijrah, corresponding to twenty fifth day of September one thousand nine hundred and twenty. References External links Husain M. Al-Baharna. The Legal Status of the Arabian Gulf States: A Study of Their Treaty Relations and International Problems. Manchester University Press, 1968. Treaties of Muscat and Oman Treaties concluded in 1920 Treaties entered into force in 1920 1920 in Asia