Behind the ancient way of life for the Tuareg tribe of the Sahara is a culture so progressive it would even make some in liberal western cultures blush.
Women are allowed to have multiple sexual partners outside of marriage, keep all their property on divorce and are so revered by their sons-in-law that the young men wouldn’t dare eat in the same room.
What is even more surprising is that even though the tribe has embraced Islam they have firmly held onto some of the customs that would not be acceptable to the wider Muslim world.
It is the men, and not the women, who cover their faces, for example.
Photographer Henrietta Butler, who has been fascinated by the Tuareg since she first followed them through the desert in 2001, once asked why this was. The explanation was simple.
‘The women are beautiful. We would like to see their faces.’
But this is certainly not the only place the Tuareg, related to the Berbers of North Africa, differ from the Muslim world of the Middle East, and even other parts of their own continent.
Before a woman marries, she is free to take as many lovers as she wants.
‘They turn a blind eye,’ explained Butler. ‘The young girls have the same great freedoms as the boys.’
For years, the men of the Tuareg have been able to ride to a young woman’s tent, and sneak into the side entrance – while his well-trained camel stands quietly and waits.
There, they will spend the night together – while the family, who all live in the tent, politely pretend not to notice.
Should the woman choose to welcome a different man into her tent the next day, so be it.
However, there is also a code of practice which none would dare break. Privacy is all important for this centuries old tribe of nomads, who once crossed the desert bringing dates, salt and saffron south, and slaves and gold north.
The idea of breaking the rules of courtship would be mortifying; as a result, the man is always gone before sunrise.
‘The Tuareg are utterly discreet. Everything is done with utmost discretion and respect,’ said Butler.
The relaxed customs around sexual partners has resulted in the girls getting married later than they may otherwise do, with the age of 20 not being uncommon.
Although, before then, they will have been wooed with poetry written by the men, who spend hours carefully crafting the words which they hope will win their beloved over.
But it is not a one-way street: the women are just as capable of putting pen to paper, using their own alphabet, taught to them by their mothers.
‘The women also make poetry eulogising the men,’ says Butler. ‘There is high romance and idolatry.’ Unlike in so many other cultures, women lose none of their power once they marry either.
Many marriages end in divorce among the Tuareg. And when it happens, it is the wife who keeps both the animals and the tent. And it is she who normally decides that she’s had enough.
His wife, meanwhile, will keep possession of everything she brought to the marriage and that includes the children.
The mother’s camp, Butler explains, is the root of the community, the home everyone returns to – and this arrangement ensures it stays that way.
And there is no shame in divorce. Families will often throw their daughters a divorce party, to let other men know they are available once more.
But this is not a matriarchal society, where the women are in charge.