From Ghandi to Gates, letters that changed the world reveal historic moments (8 Pics)

The art of writing a letter is dying out in favour of emails and texts.

Six in ten adults say they've sent fewer than five handwritten notes in the last decade. And young people hardly ever put pen to paper.

Yet some of humanity's most powerful messages were recorded in ink. Epistles from St Paul, through to Darwin, Einstein, Ghandi, Martin Luther King and Bill Gates have been landmarks in history.

As it seems like letters are heading down the road to becoming obsolete, we look at the ones that prove the pen, or typewriter, is mightier than the sword - and perhaps even the email.

Gandhi to Hitler and Britain

Nonviolent Mahatma Gandhi loved firing off a letter.

In 1939 he wrote to Adolf Hitler: "Dear Friend. You are the one person in the world who can prevent a war which may reduce humanity to the savage state. Will you listen to the appeal of one who has deliberately shunned the method of war not without considerable success?"

India's British rulers stopped the letter being sent - and Hitler invaded Poland anyway.

But a three-page letter to Britain in 1943 proved his credentials as independence leader.

Under arrest at the Aga Khan Palace in Pune, he said that with millions of Indians starving "the huge place in which I am being detained I hold to be a waste of public funds" . Independence was was finally achieved in 1947. But a year later Ghandi, 78, was shot dead in New Delhi amid religious violence.

Einstein to Roosevelt

Atomic energy was still new in August 1939 when physicist Leo Szilard heard of advances by German scientists. He asked Albert Einstein to alert his friend US President Franklin D Roosevelt by signing a letter warning "uranium may be turned into a new and important source of energy" and that Hitler could develop "extremely powerful bombs of a new type". Einstein agreed, ending: "Yours very truly, Albert Einstein." Roosevelt saw the letter on October 11 1939 and soon set up the Manhattan Project to build atomic bombs before Germany could.

In 1945 America dropped the first nukes on Hiroshima and Nagasaki in Japan. Shocked by the death toll, Szilard spent the rest of his life fighting for arms control. In 1947 Einstein told of his regret at signing the letter: "Had I known the Germans would not succeed in developing an atomic bomb, I would have done nothing."

Resignation King Edward VIII

Two paragraphs - dictated on December 10 1936 and signed by his three brothers - ended our monarchy's greatest modern crisis.

Edward was giving up the throne to marry his divorced American lover Wallis Simpson. He wrote: "I, Edward the Eighth, of Great Britain, Ireland and the British Dominions beyond the Seas, King, Emperor of India, do hereby declare My irrevocable determination to renounce the throne for myself and for My descendants, and My desire that effect should be given to this Instrument of Abdication immediately."

The Church of England, which he headed, did not allow divorced people to remarry in church if their past partner was alive.

Luckily for Prince Harry and divorced Meghan the Church's view changed by the time they wed in May.

Martin Luther King Jr from jail

The US Civil Rights leader was being held in solitary confinement after he was arrested during a mass protest in Birmingham, Alabama, in April 1963.

Denied access to a lawyer and contemplating his fate behind bars, he penned his powerful 7,000-word Letter From a Birmingham Jail on scraps of paper, in the margins of newspapers and even on yellow legal notepaper smuggled into his cell. It was his response to another open letter written by Christian and Jewish leaders which criticised his campaign against segregation.

The letter - still studied in US schools today says: "Injustice anywhere is a threat to injustice everywhere. We are caught in an inescapable network of mutuality, tied in a single garment of destiny. Whatever effects one directly, affects all indirectly."

President John F Kennedy intervened and Dr King was freed after eight days. Five years later he was assassinated. But his legacy lives on in these words.

Darwin to botanist Hooker

Charles Darwin's 1859 book On the Origin of Species shocked the world with its theory of evolution by natural selection but he had already outlined his ideas in more than 1,400 letters exchanged with a botanist pal.

In fact it was in January 1844 that he first told Joseph Dalton Hooker: "At last gleams of light have come and I am almost convinced (quite contrary to opinion I started with) that species are not (it is like confessing a murder) immutable."

He also corresponded with fellow biologist Alfred Russel Wallace - who had the same theory. One thanked him for a study on pigeons and parrots and asked how his own book was going. The Malay Archipelago took another five years!

St Paul

The Epistles of Paul, which form 13 New Testament books, are arguably the most influential letters in history. Written 50 years after the crucifixion, they address divorce, marriage, conscience, the resurrection, slavery, a woman's role in the church, how services should be conducted, parenting and salvation. Paul travelled thousands of miles spreading the word of Jesus. One passage from Corinthians is still used in weddings today: "Love is patient, love is kind. It does not envy, it does not boast, it is not proud. It is not rude, it is not self-seeking, it is not easily angered, it keeps no record of wrongs. Love does not delight in evil but rejoices with the truth. It always protects, always trusts, always hopes, always perseveres".

"Love never fails."

Bill Gates to computer 'hobbyists' around the world

In February 1976 home computers didn't do much, the internet was unheard of and a pirate was Captain Pugwash. But a 21-year-old geek called Bill Gates was worried that hobbyist users were sharing a leaked copy of his company Microsoft's Altair BASIC program - for free. Bill, 21, wrote to a computer mag: "As the majority of hobbyists must be aware, most of you steal your software. Hardware must be paid for but software is something to share? Who cares if people who worked on it get paid?"

The rant didn't make him popular. But he was right. His letter formed the foundation for rules and regulations we have today.

And Bill is now a 62-year-old global philanthropist with a £72billion fortune.