1507: The arrival of the Portuguese. Muscat is captured.
1650: The Portuguese are driven out of Muscat.
1741: Imam Ahmad bin Said expels the Iranian community.
1798: Treaty of friendship with Britain, but Oman is still independent.
1861: The ruler, not the Imam, takes the title "Sultan".
1913: Fights between the group of the imam and the one of the sultan, start. The imam gets support from inland tribes.
1920: Peace is restored.
1932: Said Bin Tamur becomes sultan.
1954: The imam (a new one) starts a new rebellion, and gets help from Egypt and Saudi Arabia.
1959: The sultan puts the rebellion down, with British aid.
1964: Oil is discovered.
1965: Revolt in Dhofar, because of the repressive politics of the sultan.
1967: Oil production starts.
1970: Sultan Said was overthrown by his own son; Qaboos bin Said, in a palace coup , it was reported that Sultan Qaboos has shot & injured his father. Qaboos introduces liberalizations of the political system, and starts many development projects. The name of the country was changed from Muscat to Oman.
1970s: Oman is plagued by civil war where Marxist groups supported by South Yemen, fight against the government forces. The sultan comes out as the victor of these fights with the support of Britain & USA.
1980: Military agreement with the USA is signed, as Oman is scared by Iranian revolution and the Soviet invasion of Afghanistan, both happening the year before.
1981: Together with 6 other countries, Oman forms the Gulf Cooperation Council.
1991: Sultan Qaboos expands and restructures Oman's consultative council.

The petty is that Sultan Qaboos has no son ( as he was never married) and he has no successor.