The appointment of Lachlan Murdoch as chairman of Fox and News Corp solidifies his position as one of the most powerful media barons in the world.

What do we know about Rupert Murdoch's eldest son and successor?

Lachlan Murdoch, 52, is one of three children Rupert Murdoch had with his second wife, Scottish journalist Anna Maria dePeyster.

Born in London, Lachlan was educated at prestigious American schools, graduating from Princeton University in 1994. His senior thesis wrestled with German philosophy and began with a quote from Lord Byron.

After leaving Princeton, he spent much of his career in Australia, managing his father's businesses.

Lachlan was once seen as the natural heir to the News Corp business. But after a feud with the then-boss of Fox News, Roger Ailes, he left the company in 2005.

Paddy Manning, an Australian journalist who wrote The Successor, a biography of Lachlan Murdoch, says the eldest son felt that his father should have backed him in the dispute.

"When he left he was determined not to ever go back to his father's company," Mr Manning says.

He set up an Australian investment firm which poured money into a range of media and marketing companies, and even an Indian Premier League cricket team.

Not all of the investments were successful, however, with his company taking a huge loss on an Australian TV network.

In 2014, he returned to his father's empire. Mr Manning says the return came at a crisis point - in the wake of the phone hacking scandal and Rupert Murdoch's divorce from Wendi Deng.

"Lachlan felt that he needed to help his dad," he says.

In 2015, Rupert named Lachlan and his brother James as co-chairmen of the film studio 21st Century Fox.

A 2017 New York Times feature described how the brothers set about trying to transform the culture of their father's company, pushing for more transparency, workplace diversity and greater cooperation between divisions.

But the film studio was sold to Disney in 2019, and James Murdoch quit the News Corp board the following year, saying in a resignation letter that he was leaving "due to disagreements over certain editorial content" and "certain other strategic decisions".

It was reported that James donated hundreds of thousands of dollars to the campaign of Joe Biden, and was frustrated with News Corp's coverage of climate change.

In his job heading Fox, Lachlan Murdoch will have to navigate the network's on-again, off-again relationship with former US President Donald Trump.

Mr Trump has appeared on Fox News countless times but has also repeatedly criticised the network and praised rival conservative channels.

Earlier this year, Fox settled a defamation suit by voting machine company Dominion for $787.5m (£640.70m). Dominion had alleged that the broadcaster helped spread Trump's baseless rumours about widespread fraud during the 2020 election, damaging its business. And Fox still faces a similar lawsuit from another voting technology firm, Smartmatic.

Lachlan Murdoch has made few public pronouncements about Mr Trump or his own politics, but Mr Manning, the biographer, says it's "no secret" that he and his father are not big fans of the former president.

"But if the Republican party does coalesce behind Trump as the candidate next year, Fox News will have no option but to support him," Mr Manning says.

His book notes that Lachlan shares "a kind of philosophical bent" with Tucker Carlson, the former Fox News host who supports Mr Trump's Make America Great Again agenda. And it also claims Lachlan Murdoch was responsible for the Fox News decision not to broadcast live US Congressional hearings into the Capitol riot.

But ultimately, Mr Manning says, Lachlan Murdoch "does not see himself as a kingmaker" in the same way that his father has often been seen across the English-speaking world.

"Lachlan sees his role as determining strategy for the business, and keeping an eye on the bottom line," he says.

The opening of The Successor also describes what Lachlan Murdoch and his wife were doing while those hearings began in June 2022.

The couple were reportedly taking a luxury yacht for a spin around Sydney Harbour, while waiting on delivery of a boat more than five times as expensive, which they planned to park in their multi-million dollar boat shed near the family mansion.

The couple also own the $150 million Chartwell Estate in Los Angeles, amongst other properties.

The Australian Financial Review recently placed him 33rd on their list of the country's richest people, with a total fortune of A$3.35 billion ($2.1 billion).