Ibadhism has always survived at the edges of the Islamic world and Ibadhis had few contacts with the other Islamic communities: they developed their own idea of government, the imamate, and Law. In Oman, the emergence of Ibadhism at the beginning of the 20th century as the basis for the construction of a “National”/Imamate identity is due to the birth of the sultanate on the coast of Oman, the influence of the Salafiyya and the diffusion of the Nah?a movement. The sultanate does not belong to the Ibadhi tradition of government: it is a bid‘a so it does not participate in the formation of Omani/Ibadhi identity but on the contrary the sultanate is rather a term of opposition in relation to which the National/Ibadhi identity is positively established. The traditional government is that of the ibadhi Salaf, the Imams, and thanks to the diffusion of the Nah?a movement the need for the constitution of an Ibadhi imamate is now possible. The aim of the paper is to point out how the formation and recognition of the Imamate of Uman, as a State, in the 1920 Sib Treaty, is closely linked to the emergence of the idea that Ibadhism is the distinctive religion of the territory where the Imamate itself was proclaimed. It follows from this that the imamate would be the natural government of the inner Omani territory during the process of the national states formation, at that time shared by all the Islamic world. So the Ibadhi identity, historically existing in the Omani territory, can now be formally expressed in the Imamate of Oman. Ibadhi Islam became the specific and distinctive feature of a limited territory for the construction of an Ibadhi State in which the Ibadhi/Omani identity is fully recognized. As it will be seen this link between territory- religion-government is well described in various historical books written in the first half of the last century, as Tu?fat al-A‘y?n bi-s?rat Ahl ‘Um?n by N?r al-D?n al-S?lim?, Nah?at al-A‘y?n bi-?urriyyat ‘Um?n by Mu?ammad al-S?lim? or ‘Um?n ‘abrá Ta‘r?kh by Ab? Hil?l al-Siy?b?.