But the history of his heart problems was no secret, and succession to the monarchy of the island kingdom had already been chosen by the emir, in accordance with the law of the land.

The emir was buried in accordance with Muslim tradition in the country's capital, Manama, meaning "place of rest" in Arabic.

A full three months of mourning has been decreed.

Ninth in line

Sheikh Isa took over as head of state after the death of his father, Sheikh Salman, becoming the ninth in a line of Bahrain's rulers from the al-Khalifa family.

The emir's son Hamad has taken power

He formally adopted the title of emir when Britain, to whom he remained a close friend and ally, granted the state its independence.

Under the emir, Bahrain became the second Arabic Gulf state to have an elected parliament, under a 1973 constitution.

But Sheikh Isa dissolved the body - and suspended the constitution - in 1975 after a showdown over domestic and regional policies.

He replaced the national assembly with a 30-member council in December 1992.

Since that time, the mostly Shi'ite opposition has rallied against the Sunni-led government for parliament's restoration in unrest that has cost at least 38 lives.

But in spite of the social unrest that has sometimes rocked Bahrain in the past four years, the emir managed to retain the affection of most of his people.

Offshore banking

The emir kept a pro-western foreign policy, leading the region economically as a financial capital with important offshore activities.

Bahrain serves as the base of the US Fifth Fleet in the strategic area between two seas in the centre of the Gulf.

It was the first country on the Arab side of the Gulf to strike oil in commercial quantities in 1932 but today the reserves are almost exhausted.

Oil production now stands at 37,700 barrels a day, though little crude oil is exported.

The ruling family

Sheikh Isa's son and heir-designate, Crown Prince Sheikh Hamad ibn Issa al-Khalifa has already succeeded as the new head of state.

The office of emir passes from father to the eldest son unless the emir designates another male relative to succeed him.

Many other male members of the al-Kahlifa clan hold top posts in the government.

Khalifa ibn Salman, the late emir's elder brother is Prime Minister, and his son, Ali ibn al-Khalifa, is Minister of Transport.

Ali ibn al-Khalifa is married to Zayn bint Khalid ibn Abdulla, the daughter of the state's housing minister, who in turn is married to Maryam bint Salman, sister of the late emir and the prime minister.

Interior Minister Mohammed ibn al-Khalifa, is a brother-in-law of the prime minister and a direct cousin of both the prime minister and the late emir.