If only Livingstone had learnt a little from his first and only convert

In the David Livingstone exhibition, currently at the National Portrait Gallery in London, there is a flat-bottomed brass bowl. It is the sort of little basin that might have been used for splashing the face with water, on a hot African morning, or perhaps for washing out bandages. Livingstone left it behind in 1851 as a gift for Sechele, chief of the BaKwena and Livingstone's only convert to Christianity.

The bowl and a daguerreotype portrait are the only relics of Sechele. Most of the show is concerned with the glamour of Livingstone's later travels, with the legend of Stanley's search and Livingstone's death. But Sechele deserves to be remembered in a special way.

For nearly six years, between 1845 and 1851, he was host to the young Scottish missionary and his family. The BaKwena, a small Tswana-speaking group, lived at Kolobeng in what is now southern Botswana, an arid region plagued by drought, lions and Boer slave-raiders. The chief built Livingstone a "house of God" and helped him to learn the language. Livingstone taught Sechele to read, and on 1 October 1848, after long preparation and examination, baptised him. But less than a year later, he convicted Sechele of backsliding and sin and banned him from Communion.

Their relationship never recovered. But it has always seemed to me the most touching encounter between Africa and Europe, between the interlace of a traditional society and the fierce individualism of Victorian Britain. It was a sort of dialogue between two ultimately incompatible moral systems. When the dialogue broke down, both men were shattered.

It is easy to respect Livingstone, but harder to like him. Look at his professions of faith. " Had I a thousand lives, they would all be dedicated to Him ... If God has accepted my service, then my life is charmed ... God had an only son, and he was a missionary and a physician. A poor poor imitation of Him I am, or rather wish to be. In this service I hope to live; in it I wish to die." Noble words, but "I" is the one that dominates.

Sechele, in contrast, thought of his duty in collective terms. What was the value of "finding Jesus" and salvation for himself, if his conversion harmed his people? And yet at first, stirred to his bones by Livingstone and his Christian message, he tried to square the circle. Preparing for baptism, he agreed to send away all his wives save one.

The BaKwena were appalled. Each wife was also a link in a web of kinship and clientship, the net of obligations that helped this frail community to survive hunger and disaster. Moreover, though the missionary did not grasp this, the denial of the chief's sexuality fractured the ethos of strength and fertility which supported the community's belief in itself.

Livingstone noted: "[Sechele's] eyes glistened ... It will be a hard trial to part with his wives. Three of them are decidedly the best scholars, the most friendly, the best in everything of all the women of the town ... They being daughters of influential persons, much excitement and opposition..." The kgotla (assembly) wept and raged at Sechele, at the disgrace of wives being returned to their families. A terrible drought ensued, and was blamed on Sechele's abandonment of his wives.

In vain, the elders (probably with Sechele's encouragement) begged Livingstone to let the chief resume the rain-making rituals. "God has given white men many things which he has not given to black men - guns, waggons &c - and he has given black men many things which are not given to white men. The knowledge of trees which can make rain is one of these, and to ask us to give up rain-making is the same as if we were to ask [the missionary] to give up his waggon."

Then, in March 1849, the belly of one of Sechele's dismissed wives began to swell. When Livingstone accused Sechele, the chief admitted in tears that he was responsible. Characteristically, Livingstone recorded his own pain first. In a letter to the missionary Robert Moffat, his father- in-law, he wrote: "The confession loosened all my bones. I felt as if I should sink into the earth, or run away ... When I thought of the reproach to the name of Christ, no one except yourself can imagine the lancinating pangs. They fell on the soul like drops of aqua fortis on an ulcerated surface."

What about Sechele's pain? He repented and said desperately: "Do not give me up. I shall never forsake Jesus or his word." But Livingstone denied him the sacraments and never forgave him. He wrote a note to the chief: " My heart is broken ... I can no longer be a teacher here."

Soon afterwards he left. In 1852, the Boers took 124 children off into slavery. A few months later, they returned in force, killing some 60 people and sacking Kolobeng - including Livingstone's house.

Sechele spent the rest of his life vainly pleading for British protection. Livingstone, who met him once more, warned him that he was wasting his time. The Boers were "a gallant brigade of Satan's own, reeking red from Pandemonium", but the British at Cape Town would do nothing to save the BaKwena, who became hunted wanderers on the margins of the wilderness.

The little brass basin gleams emptily in its showcase. Once it reflected a Scottish face with a shaggy moustache, and a broad African face with narrow eyes. What was this death of a friendship, which hurt those two men so deeply?

They were equally superstitious, only in different ways. Sechele thought that God could be persuaded to make it rain. Livingstone thought that God literally punished those who did not listen to his Word; after the Boer massacre, he wrote in his journal that "God has dealt graciously with [the BaKwena] for years and now suffers them to feel the rod of his anger".

Unlike many white men, Livingstone took the humanity of Africans seriously. He wrestled man to man with Sechele for his soul; it never occurred to him to make allowances for "a Primitive". But Sechele understood what was at stake better than he did.

The African saw human existence as part of a whole creation. Piety meant respect for society as well as individuals, for earth, water, beasts and clouds as well as for a God. The Victorian Scot saw only the desperate need for an individual to cleave to his God, a triumph worth any sacrifice.

Today, it is Sechele who seems enlightened and Livingstone who seems primitive. The chief's love for his guest made him take the risk of conversion, although he knew that Livingstone had little idea of the pain and guilt involved in that risk. He named his son Setefane (Stephen) after the first convert in the Gospels, sat on a chair made in Birmingham and began to decipher an English book about a pilgrim by "Johane Bunyane".

But it was no good. His people wept; neighbouring chiefs mocked; his beloved wives sat alone in their shame; the leaves crumbled to dust in the drought. In the end he reaffirmed the wholeness of all life in the simplest way he could, with his own body. He hoped that Jesus would understand why everything had to be joined together again.

Nothing is left of Kolobeng except a few stones in the waste. Livingstone went on his way, wretched because he had lost a soul to Satan. Now there are towns and schools named after him all over the world. But Sechele, who remained to face famine and the Boer cavalry, who understood something about life on earth which Europeans are now learning only a century and a half later - why is there no centre of wisdom named after him?