Of all the things to find in the family boxes this weekend, as my novel Mad Richard launches: this pooch, whose photo was taken in the 1870s or 80s.

Turns out it was the dog of someone mentioned in the novel: Henry Verrall. Uncle Henry Verrall, it says on the back of the photo, the handwriting scrawled under an elaborate logo:

FROM: WALKER’S Artistic Palace of PHOTOGRAPHY, King Street, CHATHAM, ONT.

Mad Richard is based on the life of Richard Dadd, the 19th century English painter who was called the most promising artist of his generation. Richard started hearing voices while on tour with a patron in Egypt, voices that would order him to commit a murder. After a famous trial, Richard spent most of the rest of his life locked up in the Bethlem Royal Hospital—Bedlam—where he painted masterpieces.

Richard Dadd was a family connection of my husband’s. He was the nephew of an English chemist named Henry Martin–or as we would say, he was a pharmacist. Henry Martin was my husband’s great-great-great-grandfather (if I’ve counted right). He immigrated to Canada with his family in 1840—a long-ago decision that in an intricately winding way led me to write the novel.

Henry Martin and Richard Dadd knew each other very well. In his early years, Henry was apprenticed to Richard Dadd’s father in his chemist’s shop in Chatham, Kent. Years later, Richard Dadd’s older brother was an apprentice in Henry’s shop in London. The families were close.

It gets more complicated here. The owner of the dog in the photograph, Henry Verrall, was Henry Martin’s brother-in-law: his wife’s brother.

Henry Verrall and two of his brothers moved to Canada during the 1830s, and their immigration would prompt Henry Martin to leave England a few years later. Oddly, Henry Martin ended up going from the town of Chatham in the county of Kent, England, to the town of Chatham in the county of Kent, Ontario, and living out his life in the pioneer village of Wallaceburg.

I’m interested in all these pings: the Verrall immigration, the Henry Martin immigration, and the effect of these decisions on the murder Richard committed. One thing didn’t lead to another, but the whole web of family life and family conflict contributed to what happened, just as a whole web of family research helped me write the novel.

My mother-in-law, Mary Martin Knox, spent more than thirty years investigating the family history. I’ve got an entire bookcase of her research in my office, and more unsorted papers in the family boxes that crowd our attic. And since her memory remains amazing at the age of 95, she can guide me through the boxes and binders.

This meticulous research was the great gift that got me started on the novel. Here’s an example: during several trips to the British archives, Mary photocopied maps of early Chatham, England, showing the exact location of Robert Dadd’s pharmacy on the High Street from the time it opened early in the 19^th century.

Richard grew up over the store—and her maps show that the store was located a few doors from the High Street pub, the Mitre Tavern. While doing my research on Chatham, I read that as a child, Charles Dickens was regularly lifted onto a table at the Mitre Tavern by his father, John Dickens, to sing and dance for patrons.

Charles Dickens was five years older than Richard Dadd. Richard would have been only five or six when Charles was turned into a performing monkey by his father. But Richard had two older brothers and his father, no abstainer, would likely have made the Mitre Tavern his local.

A historian would take this information and say, It’s possible that at least some members of the Dadd family saw the young Charles Dickens dance on a table at the Mitre Tavern. It’s also probable that Richard’s father, Robert, knew John Dickens. Robert was the Chatham town chemist. John Dickens—by all reports a sociable and talkative man—would almost certainly have patronized his pharmacy, not least because Charles was a sickly child.

No one in the Dadd or Martin family left a diary, at least that we know of, although there are family letters. In later life, Charles Dickens burned many of his own letters and papers. No one can definitively prove that the Dickens and Dadd families knew each other in Chatham, so a historian would have to hedge her bets.

But a novelist can write a scene of the Dadd family watching Charles Dickens singing on a table in the Mitre Tavern. Might have happened. Why not? (And the name is delicious.)

What certainly happened was Henry Verrall’s dog. No family stories tell us why he or she was photographed at a time when people usually didn’t photograph their pets. It was expensive to darken the door of places like WALKER’S Artistic Palace of PHOTOGRAPHY. Maybe this was a heroic dog. Saved a child from drowning. Pulled Henry out of a house fire. But that’s another story, and one I won’t write. Feel free.