An adventurer, a motoring and aviation enthusiast from their earliest days, an Edwardian character with a craggy face and a twinkle in his eye; the fifth Earl of Carnarvon was far more than “just” the man who funded the exploration that unearthed Tutankhamun’s tomb.

He had sailed a 34m yacht to the West Indies and South America and journeyed to Australia and Japan, inspired by his father, who had been Colonial Secretary, in the governments of Lord Derby and Disraeli.

The earl founded the Highclere Stud and his excitement at the invention of the motor car would be matched only by Kenneth Grahame’s Mr Toad. The family fortunes were enhanced by an extraordinary marriage to Almina Wombwell, ostensibly the daughter of an army captain but in reality the illegitimate child of Alfred de Rothschild, who was a signatory to a lucrative marriage contract providing a dowry equivalent today to £25 million.

A serious accident while motor racing in Germany in 1901 precipitated a steady decline in the earl’s health and led him to spend winters in the warmer climate of Egypt, where he began archaeological excavations and, in 1907, he met Howard Carter.

The detailed story of the earl’s full but relatively short life (he died aged 56) is now emerging thanks to the researches of Fiona, eighth Countess of Carnarvon. Incapacitated by a serious knee injury, she settled down on a sofa in her airy study at Highclere Castle, near Newbury, Berkshire, to find out more about the family into which she had married and, in particular, the enigmatic fifth earl.

Aided by archives brought down from the unlit top floor of the castle, an extensive library and cuttings from the local newspaper that faithfully chronicled the family’s activities, she began work on a biography of the fifth earl. Amid the family’s files, she also discovered hundreds of unpublished photographs taken by the earl.

When plans were announced for the new Tutankhamun exhibition in London, Lady Carnarvon broke off to work on a 92-page booklet that will be on sale at the O2 arena and online from the castle’s website. Carnarvon & Carter records the early lives of the men, Carter’s explorations in Egypt before meeting the earl and their campaigns together. It has many original photographs, drawings and paintings.

Lady Carnarvon says: “This is a typical English story of human endeavour and perseverance, of two men against the odds. They made the greatest ever archaeological discovery yet neither was properly recognised. I hope this book will enhance their legacy.”

While she pays tribute to Carter’s expertise, methodical approach and immense patience, she is also keen to underline her relative’s role in the excavations. She says: “He would sit in the sand trying to marshal 270 men and boys with little experience but much enthusiasm and was also prepared to get his own hands dirty.

“He would take part in digs and, as a keen photographer, would carry heavy cameras up the valley sides to get the best pictures. He cared hugely about the people who worked with him and was called ‘Lordy’ by the locals. He comes across to me as a generous man, very kind, very fair, an intellectual who wanted nothing but the best.” She adds that both men were shattered after the tomb was officially opened on Ferbuary 16, 1923, not just by the sheer scale of the discovery but by the worldwide attention it received, bringing a stream of visitors and innumerable administrative headaches.

Both men sought a rest but, after returning to Luxor less than three weeks after the official opening of the tomb, Lord Carnarvon’s health declined from a septic wound after he shaved over a swollen mosquito bite. Back at Cairo’s Continental Hotel he grew weaker and died on April 5, 1923 – giving credence to the theory that he was a victim of the “curse of the Pharaohs”.

Lady Carnarvon believes there may be something in the theory. “The lights did go out in the hotel when he died and nobody knows why. Here at Highclere, his dog, Susie, howled and dropped dead at the same moment as her master.” But Howard Carter, the first man to peer into the tomb, lived on to list the thousands of items inside it and arrange shipment to Cairo Museum. He died in 1939.

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