His had been a life well lived: he was an author, decorative painter and an elder of the Anglican church who helped save St James Old Cathedral from demolition.

But a new book tells how Mr Freeman took to the grave a huge secret, believed to have been hidden even from his wife.

By chance, author Jenny Sinclair discovered his real name was Edward Oxford, and that as an 18-year-old, in 1840, he was the first of seven people who tried to assassinate Queen Victoria, when he shot at her carriage.

The English authorities, keen not to stoke anti-monarchist conspiracies, didn't push for Oxford to be hung, drawn and quartered for high treason.

Instead, he was found not guilty by reason of insanity, and sent to Bethlehem lunatic asylum, better known as Bedlam.

After 27 years behind bars, the last three at Broadmoor asylum in Berkshire, Oxford was deemed sane, and a model prisoner.

The Queen agreed to his release, provided he sail to the colonies, never to return.

Oxford's friend, the Bethlehem steward George Haydon, had been an adventurer around Melbourne in the 1840s, and thought it the ideal place for a man to remake himself.

And so, on February 20, 1868, Oxford landed in Melbourne with a new name, John Freeman. Setting out to become a respectable citizen, Freeman joined the West Melbourne Mutual Improvement Society, rose to become a warden at St James, responsible for church property, and wrote articles under the name Liber for The Argus, about the city's slums, markets and racetracks. They formed the basis for an 1888 book, Lights and Shadows of Melbourne Life.

In 1881 he married a widow, Jane Bowen, and was a loving stepfather to her two children. They lived in Albert Park.

Sinclair traced Jane's elderly great-grandson, who lives in Canberra, and he said the family was unaware of Freeman's notorious past. She found Freeman's book when Googling the phrase "shadows of Melbourne". She had been trying out titles for her own book on the city's culture, now called When We Think About Melbourne.

Freeman's book's entry in the National Library of Australia's online catalogue included a note that John Freeman was actually Edward Oxford who had tried to kill Queen Victoria.

Sinclair found that in the 1950s Haydon's descendants had given the library letters that Freeman had written to Haydon in England. She wondered how the royal assailant had become a pillar of society.

Oxford's trial records and 1840 newspaper articles revealed that his father had been a violent drunk. Before the shooting, Edward was too mentally unstable to work.

Yet somehow he righted himself. Asylum records depict a model prisoner: intelligent, sane and a keen student of French, Latin and painting.

Sinclair says he was smart enough to see Australia not as exile but a second chance.

She says Freeman's life has heroic qualities in that he rose above an appalling past. But many questions remain and she is doing a PhD about him.

In his letters to Haydon, Freeman regretted hurting his family and the Queen. "He wanted her to know that the foolish boy of half a century ago had done well for himself."

A Walking Shadow: The Remarkable Double Life of Edward Oxford by Jenny Sinclair, $20, Arcade Publications.