On this day, in 1929, Martin Luther King Jr was born in Atlanta, Georgia to parents Reverend Martin Luther King Sr and Alberta Williams King.

Martin was originally born "Michael King" but, following a family expedition to Europe in 1934, both father and son changed their names in honour of the German Protestant leader, Martin Luther.

In 1964, King Jr became the youngest person ever to receive the Nobel Peace for his efforts to end racial segregation and discrimination, often through civil disobedience and over non-violent means.

Perhaps inevitably, King's influence in the socially-divided United States was too much for some. He was assassinated on April 4, 1968, aged just 39.

Today, King's legacy as a human rights icon, and the impact of his work in securing civil rights progress in the US, cannot be overstated. He has since been recognised as a martyr by two Christian churches.

Recently, King was voted second in a list of widely admired people of the 20th Century, compiled by Gallup, and came third in AOL's Greatest Americans poll.

And, in the era of the US's first black President, his memory is still strongly evoked.

For instance, it is not a coincidence that President Barack Obama's Inaugral Acceptance Speech took place 45 years to the day of King's famous "I have a dream" speech, on the steps of the Lincoln memorial.

Like other great political icons - from George Washington to Abraham Lincoln - Martin Luther King Jr's presence is felt strongly in the memorabilia market, thanks to collectors and institutions eager to preserve his legacy.

A key piece of King memorabilia is one documenting the his ideals and thoughts: the seminal book, Stride Toward Freedom, published by Ballantine Books in 1961.

A signed copy, inscribed "To Dick Van Aernam, With Best Wishes, Martin Luther King, Jr" in crisp and clear ballpoint pen is currently available on the market, priced £6,000.

The book, like the man who wrote it, remains an essential piece of American history.

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