From the late 18th century, the traditional trade network in the Indian Ocean transformed and expanded as a result of changes in the world trade network caused by the industrialization and modernization of the Western world. England, France and other Western powers had firmly established themselves in the Indian Ocean region. Western capital and technology began to dominate regional trade.
Oman suffered from the declining role of its ports in the Gulf. The abolition of the slave trade, although supported by the Omani ruler, decreased revenues. With the demise of Sayyid Said bin Sultan in 1856, Oman and Zanzibar became separated, although both continued to fall under the rule of members of the Al Bu Said, even after Britain declared Zanzibar a British protectorate in 1891. It had been agreed that Zanzibar was to pay Muscat 40,000 Maria Theresa Thalers annually (also known as ‘crowns’), but the Sultan in Zanzibar stopped paying the dues shortly after the partition. The British Government of India took over this payment, thus increasing British influence both in Oman and in East Africa. Oman was cut off from its main sources of wealth, slowly becoming a stagnant backwater.
These events and their negative effects had repercussions for the country’s stability. In 1869, the Imamate was re-established in inner Oman. In essence, the tribal leaders were contesting the legitimacy of a weakened secular rule that had assumed central authority. They organized incursions into Muscat, where the ruler resided. He was dependent on British support, which was contested by the interior tribes.
For several decades rebellions flared up for various reasons, until in 1920 a treaty was negotiated (Treaty of al-Sib or al-Seeb) which basically gave the Imamate and the Sultanate their relative independence and the right to conduct their own affairs. A peaceful period followed during which the Imam and the Sultan, Said bin Taymur, corresponded regularly.