When retired teacher Rob Upward found a mysterious postcard in an album that had belonged to his grandmother, he had no idea it would take him on a journey across the Atlantic and lead to him publishing his first novel at the age of 73.

Born and raised on the Isle of Wight, where he lived before moving to Brighton in 1975, Upward was unaware that his family had any connection to America.

Yet the postcard showed a scene from what appeared to be the American Midwest during the late 1800s and was addressed to his great-grandfather.

Although he quickly worked out the initials SD on the postmark stood for the state of South Dakota, he was left stumped by the place name – Ada.

“There was no such place as far as I could see,” says Upward.

But after contacting a newspaper in South Dakota, it emerged that there had once been a town called Ada – and his great-uncle, Walter Mansbridge, had founded it.

“It turned out my great-uncle had emigrated from the Isle of Wight in 1885 and had found work in a mill in Minneapolis. He sent for his wife to join him and they ended up founding a township he called Ada after one of their daughters.”

Ada collapsed during the Great Depression in the 1930s but after Upward’s letter to the newspaper, a number of people who remembered it came forward.

The story that emerged so intrigued him that in 1997, Upward and his late wife decided to retrace his greatuncle’s footsteps and made the journey to South Dakota, where they met family descendants still living in the area.

Little was left of Ada but the foundations of the schoolhouse, post office and a few dwellings.

“It was very strange to stand there and think of my ancestors travelling from the sleepy Isle of Wight to this great expanse of land across the Atlantic. It was a different world to anything I’d ever known so I can only imagine what it was like for them.”

Upward was particularly fascinated by the story of his great-aunt, who had never left the Isle of Wight prior to taking herself and her three children off to America.

“It seemed incredible that this quiet country girl should have found herself in the middle of frontier America running the post office and stores and dealing with golddiggers and Native Americans.

“My great-uncle was a restless fellow and while he wanted to get out of England because he’d heard there was money to be made, when he got to America he became terribly homesick and ended up returning home. She was left there to run the business.”

After writing a short booklet on this intriguing chapter of his family history, he found the story of his great-aunt wouldn’t go away and so began work on Ocean Of Grass, a novel based on her story. Just released for e-readers, the novel looks at what it was like to be a female settler in the pioneering days of the 19th century.

“Generally it was the men who led the way, caught the vision, sought a freer and more prosperous life in the expanding territories. Women had little option but to follow their man but my great-aunt really made the best of it. I sought to record her courage and fortitude and pay tribute to her stoic heroism.”

After 20 years as headteacher of the former Uplands special needs school in Hollingdean, Upward came to writing late in life but has gone on to help found a writing group – the Saltdean Scribblers – and is now working on a collection of travel stories.

Discovering the adventurous lives of his ancestors encouraged him to head off the beaten path himself and he has recently travelled solo to Australia and Alaska.

“I wanted to write about my experiences as an older person travelling alone. Since my wife died I’ve been to various places and I find people are either fascinated or bemused by single travellers. Certainly I’ve met some interesting people and had experiences you don’t tend to have when you travel with someone else.

“It’s not something I thought I’d find myself doing but I thought, if my ancestors managed to reinvent themselves, why shouldn’t I?”

* Ocean Of Grass is out now, available from Amazon. For more information, visit www.oceanofgrass.com.