Umaru Yar Adua will be the country's first leader to have been university educated [AFP]

Softly spoken in public, he was backed by Olusegun Obasanjo, Nigeria's then leader, as the People's Democratic Party's presidential candidate.

Obasanjo's backing and international concern over fraud in Nigeria's election process have left many feeling it will be continue to be Obasanjo who wield's the real power.

But Gbemi Saraki, a Nigerian senator and a member of Yar Adua's campaign team, insisted the new president "will be nobody's stooge".

A Muslim, Yar Adua family has been heavily involved in Nigerian politics. His father was a minister in the first post-independence cabinet and his late elder brother was number two in Obasanjo's military government from 1976 to 1979.

For eight years Yar Adua presided over the poor agrarian state of Katsina, in Nigeria's semi-arid far north where he was said to have carefully managed state finances, improved the road network and built schools.

But he failed to deal with state's water shortages or ensure food security and his critics have said he had a number of lucrative building contracts given to his friends and relatives. Accusations that Yar'Adua denies.

Yar Adua suffered a serious kidney complaint in 2000 and in the build-up to elections and it was said that he was seriously ill, a rumour he tried to dismiss in January by challenging his critics to a game of squash.

But on March 6 he unexpectedly interrupted his campaign to seek medical care in Germany.

His aides said he was suffering from exhaustion, but his efforts to convince the electorate that he is in good health have not been wholly successful.