This is the unlikely tale of how a young man from the Australian outback took US president Theodore Roosevelt on an African safari — all with the blessing of one of the world's greatest museums.

The young fellow also wrote about the execution by the British of Boer War soldier Breaker Morant.

The adventurous Australian's name was Victor Newland but, as his granddaughter Leonie Matheson explains, his family simply called him Marra.

"He was born in 1876 on the Marra station up on the Darling near Wilcannia," Mrs Matheson said.

"Marra is actually his middle name, which is why we called him that."

One of Victor Newland's defining characteristics was, obviously, a great sense of adventure.

When the Boer War broke out in 1899 between the British and Dutch settlers in South Africa, Newland joined the South Australian Mounted Rifles.

Many of the animals hunted on safari in South Africa ended up at the Smithsonian. ( ABC News: Tom Fedorowytsch )

Mrs Matheson said the advice Newland received from his own father before setting off was a little brutal.

"He said, 'I don't expect you to win the VC [Victoria Cross], but if you are a coward, don't come home' … not exactly encouraging is it?"

And not necessary, as it turned out, either.

Victor Newland earned the Military Cross.

Once the war was over, Newland and another South Australian, Leslie Tarlton, decided to stay on in Kenya and start a business.

Their firm, Newland and Tarlton, ran safaris for wealthy hunters — businessmen, aristocrats and even presidents.

Theodore "Teddy" Roosevelt spent nine months on safari in South Africa. ( Supplied: Leonie Matheson )

An African safari with the US president

According to Professor of American history, Don De Bats, it is no accident the 26th US president, Theodore "Teddy" Roosevelt, ended up in Africa in 1909.

"Roosevelt had a habit of retreating to wilderness areas at change points in his life," Dr De Bats said.

"His first wife died just after their first child was born, and then his mother a few hours after that. Roosevelt gave the child to his sister and escaped to the wilderness … he became a frontiersman, dressed up like one and he shot a lot of things there too.

"With Africa, he'd just finished his presidency and wasn't really sure of what to do next."

The safari was formally known as the Roosevelt-Smithsonian expedition, with the prestigious Washington-based museum keen to add to its natural history collection.

Mrs Matheson said it was a vast undertaking, lasting nine months.

"With the Roosevelt expedition it was up to grandfather to provision it … he stayed in Nairobi to do that, while Tarlton went out with them [the safari party]," Mrs Matheson said.

"The food came from Fortnum and Mason in London, there were gun carriers, blankets, sheets, under sheets, tents, baths, chairs, tables, everything had to be carried.

"I know on the Roosevelt expedition they allowed 30 porters per person … it was extraordinary, I don't know how he [Victor Newland] did it."

Leonie Matheson can recall her grandfather's vivid imagination and Africa was never far from it. ( ABC News: Simon Royal )

'I find it hard to forgive killing 11,000 animals'

The scale of the safari was only exceeded by the extent of the slaughter — thousands of animals, many of them rare species, even in 1909.

That horrifies both Dr De Bats and Mrs Matheson, but it also points to complexities and contradictions at the heart of Roosevelt's character.

"I find it very hard to forgive killing 11,000 animals, but as a politician Roosevelt did all manner of courageous and good things … and he did some pretty awful things too … he was not a straightforward person, despite his image," Dr De Bats said.

Mrs Matheson says it was "unforgivable" so many animals were killed.

"It was unnecessary and you can't tell me it was all about science. They even shot a dormouse! I mean, poor dormouse!

Victor Newland's talents weren't just confined to his personal papers, he filed for newspapers in Africa and Australia. ( Supplied: Leonie Matheson )

Like Teddy Roosevelt, Victor Marra Newland too was a person of many facets.

He was a beautiful and accomplished writer. His prose was not at all like the treacly, turgid stuff favoured by many Victorian-era diarists.

Newland's talents were not just confined to his personal papers, he filed for newspapers in Africa and Australia.

Victor Newland knew Breaker Morant, the famous horse trainer whom the British executed for killing Boer prisoners of war.

Mrs Matheson still has her grandfather's type-written account of Morant's final moments before the firing squad.

There's no mention of the famous line used in the film — "shoot straight you bastards" — but the Breaker's defiance is clearly there.

"I catch a glimpse of tawny fearless eyes, alight with understanding and pity for the man who must call death upon him. Lightly he swings his hand to his breast, 'there boys', he says, 'don't miss'."

The firm, Newland and Tarlton, still exists today, though the family's connection to it ended years ago.

Victor Marra Newland returned to Adelaide in the 1920s, becoming a stock broker and a member of the South Australian Parliament.

Leonie Matheson recalls her grandfather's vivid imagination — Africa was never far from it.

"He used to get the cat and have it make paw marks in the gravel," she said.

"He'd put silver Kenyan pennies in the prints for us to find. That was my thing for Easter, we didn't have chocolate eggs then, but the pennies were much more exciting I think … we adored him."