A Portuguese interlude: 16th - 17th century AD

The small tropical island of Zanzibar, a mere twenty miles off the east coast of Africa, has played a part in local history out of all proportion to its size. The reason is its easy access to traders and adventurers exploring down the east coast of Africa from Arabia. Islam is well established in this region by the 11th century.

During the 16th century there is a new category of visitor arriving from the south - the Portuguese. They establish friendly relations with the ruler. By the end of the century there is a Portuguese trading station and a mission run by Augustinian friars. But in the late 17th century the Christian presence comes to an end, after a forceful campaign down the coast by the Muslims of Oman.

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.

British involvement: AD 1856-1885

By the time Majid inherits the throne in Zanzibar, the British are increasingly involved in this prosperous offshore island. In this same year, 1856, Burton and speke make this the base for their exploration into the interior. Their route towards Lake Tanganyika is along the tracks frequented by Arab traders, through territory which the Omani sultans of Zanzibar claim as their own.

By the time Majid dies, to be succeeded in 1870 by his brother Barghash, the British have appointed a consul to Zanzibar. His primary task is to end Zanzibar's notorious slave trade. This purpose is achieved by a treaty with Barghash in 1873.

The consul who achieves this treaty is John Kirk. It is poignant for him that this is the year in which he does so. For it is also the year in which David Livingstone, the great anti-slavery explorer, dies in the African interior. His embalmed corpse is carried by his assistants all the way back to Zanzibar.

Kirk, who receives Livingstone's body in his role as consul, has been an intimate friend. For five years, from 1858 to 1863, he accompanied all Livingstone's expeditions in the role of doctor and naturalist. He too has witnessed at first hand the brutal activities of the Arab slave traders in the interior. Livingstone would be pleased to know that their main market is now closed to them.

Well aware that Zanzibar needs to replace slave revenue with legitimate economic activity, Kirk is assiduous in encouraging Barghash to build up the export of rubber and ivory - brought from the interior of the continent, where the sultan wields a somewhat loose and ramshackle authority through Tabora and on to Ujiji.

By the mid-1880s the sultan is earning a fortune from these sources, but Kirk proves powerless to protect him from a new threat. In 1884-5 there are reports of a German, Karl peters, snooping around the caravan routes to the Great Lakes. In March 1885 there comes the astonishing news that Germany is claiming a protectorate in this inland region. And in August there is an alarming sight from the verandah of the palace.

A German-British carve up: AD 1885-1886

On 7 August 1885 five German warships steam into the lagoon of Zanzibar and train their guns on the sultan's palace. They have arrived with a demand from Bismarck that Sultan Barghash cede to the German emperor his mainland territories or face the consequences.

But in the age of the telegram, gunboat diplomacy is no longer a local matter. This crisis is immediately on desks in London. Britain, eager not to offend Germany, suggests a compromise. The two nations should mutually agree spheres of interest over the territory stretching inland to the Great Lakes. This plan is accepted before August is out.

The embarrassed British consul finds himself under orders from London to persuade the sultan to sign an agreement ceding the lion's share of his mainland territory, with the details still to be decided. In September the German gunships begin their journey home. A joint Anglo-German boundary commission starts work in the interior.

By November 1886 the task is done and the result is agreed with the other main colonial power, France. The sultan is left a strip ten miles wide along the coast. Behind that a line is drawn to Mount Kilimanjaro and on to Lake Victoria at latitude 1° S. The British sphere of influence is to be to the north, the German to the south. The line remains to this day the border between Kenya and Tanzania.

British protectorate: AD 1890-1963

After the abrupt redistribution of the sultan's inland territories, Britain remains the only colonial power with a well-established presence in Zanzibar itself. With the approval of the sultan the island and its narrow coastal regions are declared a British protectorate in 1890.

Although only wielding a fraction of their former power, the Arab sultans of Zanzibar are still during this colonial period the most influential Muslim leaders in east Africa. But their rule comes to an end soon after the island's independence in the 1960s.

A new constitution, introduced in 1960, provides for a legislative assembly. The emerging political parties are split largely on ethnic lines, representing Arab and African interests respectively, and disagreement about the franchise delays the introduction of internal self-government until June 1963. It is followed in December by full independence and membership of the British Commonwealth.

A coalition of Arab parties forms the first government, with the sultan as head of state. But in January 1964, a month after independence, a communist-led revolution topples the regime. The sultan is deposed and a republic proclaimed.

The revolution, carried out by not more than 600 insurgents, involves considerable acts of violence against the Arab and Indian populations of the island - most of whom make a hasty departure.

Abeid Amane Karume emerges as president of the resulting one-party state. His first step is to negotiate for union with neighbouring Tanganyika, also left-wing in its policies though not Marxist. The two nations are merged in April 1964, becoming the United Republic of Tanzania, with Nyerere as president and Karume as vice-president. But Zanzibar retains its revolutionary council and often continues to go its own way, to the discomfiture of the government in Dar es Salaam.