History of Sultan Said bin Taimur:
Sultan Said bin Taimur inherited in 1932 a bankrupt and politically deeply divided country from his father Taimur bin Faisal.
The father of Said bin Taimur also already inherited a high public debt and widespread rebellion among the tribes in the interior.Between 1915 and 1920, the Sultan's forces were aided by British financial and material support against the rebel tribes, ensuring adequate resistance but not total victory. An uneasy situation of no war, no peace, existed, with the sultan controlling Muscat and the coastal towns and the Imam ruling the interior. This was tacitly codified in the Treaty of Seeb in 1920, brokered by the British political agent in Muscat. The treaty was between the sultan and the tribes, represented by Sheikh Isa bin Salih al Harthi, leader of the Al Harthi tribe. In return for partial autonomy (on local affairs), the tribes in the interior pledged to cease attacking the coast. The Sultan would also make some annual payments to the tribes. The Treaty of Seeb was, de facto, a partition agreement between Muscat and Oman (i.e. coastal areas and the interior) serving Britain's interest in preserving its power through the office of the sultan without having to dispatch British troops to the region ( divide and rule).
From 1800 the Sultan of Oman also had to pay "protection" fees to the Saudi's to prevent violent attacks on Oman from their Wahabi tribes.
During the 19th and early 20th century the major interest of the British in the coast of south Arabia and the East African coast was to protect the economically crucial shipping lanes between India and Britain (i.e. avoid piracy and unrest) This became even more important after the opening of the Suez canal.
By the 1950's the Americans had secured energy sources (oil) and political influence in Saudi Arabia, Iran and most other key places in the Middle East while British influence in that region had largely diminished. The British were afraid to completely loose direct access to oil and influence in the Middle East. Also the influence of the cold war with Russia was felt in the Middle East during that period.
In 1955 drilling started in Oman at Fahud and this looked very promising. Because of the possibility of oil deposits in Oman the Saudi's started in 1955 disputing the border between Saudi Arabia and Oman and claimed the border town of Buraimi. The Buraimi Dispute was eventually taken to the United Nations, to avoid a military conflict. It was decided that the town was Omani, this decision was also simplified by the fact that Saudi had tried to bribe officials with suitcases of money...
From 1955 the the Saudi's trickered a revolt in Nizwa and the Jebel Akhdar region of Oman. With help of the British army the rebellion was quickly contained. However a few hundred fanatic rebels remained active in the Jebel Akhdar mountains and plains. In 1959 a combined land and air offensive ended the rebellion.
Since the 1920 Seeb treaty, Muscat and its interior (Oman) had been largely separate but in 1959 Sultan Taimur reunited the country. The well written book "Sultan in Oman" by Jan Morris (ref 1) gives a wonderful insight in the first part of the Jebel Akhdar campaign. It would take until 1970 for Sultan Qaboos to change the country's name form "Muscat and Oman" to its original name Oman.
The limited income of the Sultan of Oman was the Zakat (an Islamic tax on certain products), some customs taxes and some subsidies / loans from Britain. Sultan Taimur. managed his budget very closely.
The initial expectations of oil production at Fahud turned out to be too optimistic and proper oil production in Oman only started in 1967 When the financial situation and opportunities for Oman dramatically improved the old Sultan stuck to his old conservative policies, thereby obstructing the progress of the country resulting in discontent and an uprising in the country. In 1970 Sultan Taimur was peacefully removed from power by his son Qaboos with the help of the British. In 1970 Oman was one of the few countries in the world without National Debt.
Conclusion: The 1920 treaty of Seeb ensured political peace between Muscat and Oman that lasted until the 1950s, when oil exploration in the interior reintroduced conflict (insticated by the Saudi's). In return for accepting a truncation of his authority, the sultan received in 1920 a loan from the British government with an amortization period of ten years, sufficient to repay his debts to merchants. When Sultan Taimur ibn Faisal abdicated for financial reasons in 1932, the twenty-two-year-old Said ibn Taimur inherited an administration that was again deeply in debt and totally dependent on the British government. The previous also explains why until 1970 the name of Oman was "Muscat and Oman" and also why Sultan Said bin Taimur was so reluctant to loosen financial controls when the oil income started in 1967. If the British had not intervened in 1950's, Oman or large parts of it may have been taken over by Saudi Arabia.