By BBC News Online's Dylan Reynolds

The Karmapa Lama is the spiritual leader of one of the four major schools of Tibetan Buddhism, ranking only behind the Dalai Lama and Panchen Lama in the Tibetan spiritual hierachy.

As head of the Kagyu school of Tibetan Buddhism, the Karmapa is a revered Tibetan figure.

The present Karmapa - Ugyen Trinley Dorje - was also the first high lama to be recognised by China's communist government.

The long search

Karmapa Living Buddhas belong to the oldest line of Tibetan reincarnations, stretching back to the 13th Century.

The Mongolian ruler Kublai Khan is said to have presented the first Karmapa with a black hat to mark his authority.

The search for the present Karmapa began after the death of the 16th Karmapa in November 1981.

Four senior lamas - Situ Rinpoche, Shamar Rinpoche, Jamgon Kongtrul and Gyaltsab Rinpoche - were responsible for finding his reincarnation, according to the website of the Tibet Information Network (TIN).

In March 1992, Situ Rinpoche announced that he had discovered a prophetic letter from the 16th Karmapa which led him to a boy in Eastern Tibet.

Jamgon Kongtrul was on his way to Tibet to find the candidate, when he was killed in a car crash.

Shamar Rinpoche withdrew his support for Situ Rinpoche and his candidate, beginning a dispute that has continued to the present day.

On 7 June, 1992, however, the Dalai Lama announced his official support for the candidate.

China allowed a search team to travel to Eastern Tibet where they found the boy - a nomad's son - and formally identified him as the 17th Karmapa.

Dalai Lama's vision

Before the boy was found, the Dalai Lama is said to have had a vision in which he saw green mountains covered with meadows and two streams, where the name "Karmapa" resounded in the air.

Later, when the search party came to Barkor, the community where the boy was born on 26 June, 1985, this is exactly what they found: Green meadowed mountains in an area sparsely populated with two rivers on each side of the valley.

According to the Tsurphu Foundation website, the boy's parents told them their son would often ride off on jackals and goats into the mountains alone.

"He built toy monasteries and a throne of stone and earth, where he would sit and recite prayers.

"When others were killing animals, he would look at them with great compassion and shed tears."

Chinese support

The boy was taken to Lhasa on 13 June, 1992. The Chinese authorities announced their support for him on 27 June - on the same day that the boy carried out his first religious ceremony.

Enthronement took place at Tsurphu monastery, the traditional seat of the Karmapa, on 27 September 1992, attended by Chinese officials.

However, controversy over the reincarnation began when Shamar Rinpoche announced he did not accept the authenticity of the letter produced by Situ Rinpoche. In 1994 he produced a rival candidate, Thaye Dorje, who he and his followers continue to claim to be the real Karmapa.

Shamar Rinpoche and Thaye Dorje are said to be travelling in Europe.

Controversy over visits

Since his enthronement at the Tsurphu monastery in 1992, the boy has visited China twice and met some of its highest officials, including President Jiang Zemin.

Last year, he is reported to have met the number four in the communist hierarchy, Li Ruihuan, who said the Karmapa's "progress" would have a "great impact on the development and stability of Tibet".

After the visit, the Karmapa was quoted by the official press as saying he had "received an education in patriotism", according to the TIN website.

The statement quoted him as saying he would "follow the instructions of Jiang Zemin" and "work hard for the unification of the motherland and national unity".

His first China tour in 1994 was reported to have sparked protests in the Tsurphu monastery - leading to the detention of six monks.

TIN says that, according to Tibetan sources now in exile, posters appeared in the monastery in late 1994 denouncing the Chinese Government for not allowing the Karmapa to visit India.

TIN said he had fled Tibet because he was denied access to his teachers, including Situ Rimpoche, who is living in India.