The Al Hajar Mountains, of which the Jebel Akhdar is a part, separate the country into two distinct regions: the interior, and the coastal area dominated by the capital, Muscat. The British imperial development over Muscat and Oman during the 19th century led to the renewed revival of the cause of the Imamate in the interior of Oman, which has appeared in cycles for more than 1,200 years in Oman. The British Political Agent, who resided in Muscat, owed the alienation of the interior of Oman to the vast influence of the British government over Muscat, which he described as being completely self-interested and without any regard to the social and political conditions of the locals. In 1913, Imam Salim Alkharusi instigated an anti-Muscat rebellion that lasted until 1920 when the Sultanate established peace with the Imamate by signing the Treaty of Seeb.The treaty was brokered by Britain, which had no economic interest in the interior of Oman during that point of time. The treaty granted autonomous rule to the Imamate in the interior of Oman and recognized the sovereignty of the coast of Oman, the Sultanate of Muscat. In 1920, Imam Salim Alkharusi died and Muhammad Alkhalili was elected.