There is a joke that goes something like this: Karl Marx, the German philosopher whose ideas became the intellectual foundation of modern communism, also had a sister, who invented the 100m dash. Her name was Onya.

The truth is that Marx did have a sister, although she was not called Onya, but she did play an influential role in 19th century South Africa.

Karl’s younger sister was actually called Louise. She was born in 1821, three years after Karl, in the city of Trier, in the then Prussia, and what is today modern Germany.

In 1853, Louise married a Dutchman, Jan Carel Juta, and the couple decided to emigrate to the Cape Colony in what would become modern South Africa.

On the way to the Cape, Jan and Louise visited Karl in London, where he now lived, but Louise was unimpressed with her older brother’s views. According to a guest who attended a dinner party at Karl’s home where Louise was a guest, Louise “could not countenance her brother being the leader of the socialists, and insisted in my presence that they both belonged to the respected family of a lawyer, who had sympathy of everyone in Trier”.

When Jan and Louise got to the Cape, they founded Juta and Company, which still exists, and which is South Africa and Africa’s leading publisher for regulatory, business, and academic content today.

Their first shop was opened in Wale Street in Cape Town.

Jan, a qualified lawyer, had brought a law library with him from the Netherlands, but his shop did not only stock law books. It sold everything from magazines to cologne to Bibles to cigars. Jan and Louise soon opened shops in cities and towns across what is today South Africa.

Jan also recognised the need to document legal precedents in the Cape’s Roman Dutch legal system, publishing his first summary of cases in 1869. His Law Reports eventually covered cases dating back to 1828 and became a vital resource in South African jurisprudence.

Jan died in 1886 and Louise died in Rondebosch in 1893. However, the company they founded endured. Today it is possibly the largest non-listed public company in South Africa’s history.

One of Jan and Louise’s sons, Henry, had a successful legal and political career. He served as a member of the Cape Parliament as well as its Speaker. He also served for a brief period as the Cape Colony's attorney general, under Prime Minister Cecil John Rhodes. After Union in 1910, Henry also served as a judge. He died in England in 1930.

So next time you hear about Karl Marx and the pernicious legacy the ideology he developed left the world, remember that his sister and her family had a far more positive influence on the planet.