Well placed for trade: from the 6th century BC

Like Yemen to the southwest, the territory of Oman has always benefited from its fine trading position at the southern extremity of the Arabian peninsula. From here merchants, without needing to sail far from land, can make easy contact with Persia to the north, India to the east and Africa to the south. This stretch of coast, together with that of Muscat just round the corner, is valuable territory.

From the 6th century BC until the arrival of Islam, some 1200 years later, both Muscat and Oman are under the control either of the Persian empire or of rulers from neighbouring Yemen. In the 7th century AD, like the rest of Arabia, they acquire new masters - the Caliphs of Medina.

However it is only another century before Muscat and Oman evolve their own local system. From 751 they choose imams to rule the region as spiritual leaders. This elective theocracy lasts for the surprisingly long span of four centuries - until 1154, when Banu Nabhan suceeds in establishing a dynasty of hereditary kings.

The Nabhanite dynasty maintains itself in power for three centuries, until in 1429 its authority is again challenged by an elected imam. The struggle between imam and hereditary king or sultan becomes from this time a feature of Omani history.

From the early 16th century there is a third contender on the scene - the Portuguese, opening up their trade route to India. In 1507 Portuguese vessels enter the Gulf of Oman. They sack the town of Muscat and establish control of the neighbouring region. This control is strengthened after 1514, when they capture the island of Hormuz and plant a permanent garrison there.

For the rest of this century the Portuguese are the strongest sea power from the Gulf of Oman to the southern tip of Africa. But by the mid-17th century the Omanis are in a position to fight back. The imam Sultan bin Saif recaptures Muscat from the Portuguese in 1650. His son, Saif bin Sultan, is ready to extend the conflict down the African coast.

Oman and Zanzibar: AD 1698-1856

In the 1690s Saif bin Sultan, the imam of Oman, is pressing down the east African coast. A major obstacle is Fort Jesus, housing the garrison of a Portuguese settlement at Mombasa. After a two-year siege, it falls to Saif in 1698. Thereafter the Omanis easily eject the Portuguese from Zanzibar and from all other coastal regions north of Mozambique.

Zanzibar, a valuable property as the main slave market of the east African coast, becomes an increasingly important part of the Omani empire - a fact reflected by the decision of the greatest 19th-century sultan of Oman, Sa'id ibn Sultan, to make it from 1837 his main place of residence.

Sa'id builds impressive palaces and gardens in Zanzibar. He improves the island's economy by introducing cloves, sugar and indigo (though at the same time he accepts a financial loss in cooperating with British attempts to end Zanzibar's slave trade).

The link with Oman is broken after his death in 1856. Rivalry between his two sons is resolved, with the help of forceful British diplomacy, when one of them (Majid) succeeds to Zanzibar and to the many regions claimed by the family on the east African coast. The other (Thuwaini) inherits Muscat and Oman.

The Sultanate of Oman: to AD 2000

Thuwaini and his descendants remain in control of Oman from his inheritance in 1856 to the present day. Indeed their dynasty is older than this, for it is first established in the 18th century by his ancestor Ahmad bin Said al Busaidi. Elected imam in 1741, Ahmad is succeeded in the role in 1775 by his son. Contriving to keep the office within the family, his descendants gradually become accepted as a hereditary line of sultans.

From 1798 the sultans have the support of the British, who in that year make Oman a protectorate. By the late 19th century British help is needed mainly against Imams, now again being elected in Oman's traditional manner.

The Imams' power base is among the tribes in the interior of the country, at Nizwa, from which tribal leaders emerge from time to time to attack the sultan's coastal territories. By 1920 the power of the imam and his allies is such that the British negotiate the treaty of Al-Sib, by which the sultan allows internal autonomy to the Nizwa region.

By the 1950s this is not enough. The imam and a powerful tribal leader enlist the help of Saudi Arabia in setting up an independent state. With British help the rebellion is suppressed by 1959. But the 1960s bring another threat, in the formation of a Marxist guerrilla movement - the PFLO, or Popular Front for the Liberation of Oman.

The PFLO involve themselves in an existing minor rebellion in the hill regions of the southern province of Dhofar. From 1968 they succeed in escalating this into a serious threat to the regime.

The crisis prompts a palace coup in 1970, in which Sultan Sa'id is overthrown by his son, a Sandhurst-trained officer, Qaboos bin Sa'id. With the help of British, Jordanian and Iranian troops Qaboos crushes the PFLO by 1975. Since that time the sultan has ruled in unashamedly royal style. He uses the modern trappings of a cabinet of ministers, but reserves for himself the portfolios of prime minister, foreign minister, finance minister and minister of defence. In 1996 he formally defines Oman as a hereditary absolute monarchy.

The sultanate of Oman has been the nation's name since the beginning of Qaboos' reign (he changes it from Muscat and Oman in 1970, after his coup against his father).

At the time of Qaboos' seizure of the throne, Oman's modern source of wealth is just beginning to materialize. The national petroleum company, jointly owned with Shell, begins exporting oil in 1967. By the end of the century production is approaching a million barrels a day. Meanwhile there are plans underway to develop Oman's reserves of natural gas.