In C.J. Sansom's fifth Tudor mystery, Heartstone, lawyer Matthew Shardlake finds a link between a young man driven to suicide and a mad woman incarcerated in Bedlam that could have terrible political repercussions.

Why have you set your whodunits during the Tudor era?

It was a period of such revolutionary change in English history, and I was interested in how the changes affected ordinary people. The Reformation turned religious practice, which was an intimate part of the lives of most people, upside down and inside out, and the arguments over what the state religion should be made politics more vicious. The brutal political authoritarianism of Henry VIII was something quite new in England. I have tried to stay faithful to my aim of telling stories that feature all classes in Tudor society, and showing the great upheavals that took place, and how life for most people was perilous, dirty, and short.

What do you think are people's biggest misconceptions about Henry?

The biggest one is that Henry was a successful monarch. Certainly he has become a larger than life figure in England. In fact, in my opinion, he was a failure. His changing his mind every few years between radical and conservative religious policies meant that he left a legacy of religious uncertainty and battling between Catholic and Protestant factions. The extraordinarily spendthrift nature of his regime led to unprecedented taxation, debasement of the coinage, inflation, and social unrest. Most of the population actually got poorer during his reign. His several wars against France and Scotland were spectacularly unsuccessful and left England isolated in Europe.

Are there any living persons who resemble Henry VIII?

Take any authoritarian ruler who thinks he is right all the time and that God is on his side, add viciousness and a readiness to kill people, and you have a sort of template.

There have been reports of a TV series. Is one in the works?

It's been in discussion and development for years, with Kenneth Branagh possibly playing Shardlake. I hope it may come off one day.

Are there historical antecedents for having a lawyer investigate crimes?

No. Murder investigations at the time were carried out, often not very effectively, by the coroners. I wanted to have an investigator who would pursue complicated problems over time and decided a lawyer was well fitted for that role. When I was a lawyer, I practiced mostly personal injury and landlord and tenant law, acting for claimants. That background and land law, and knowledge of legal culture and procedures, have been very helpful in writing the Shardlake books.