I can't remember the bookshop, or the city where it happened. I can't even remember which book I was promoting, or much about the reader who asked it—but I'll never forget the question.

After I'd finished my talk—about the latest title in my Roma Sub Rosa series of historical mysteries set in ancient Rome—the time came for q&a. A man stood up. “Mr. Saylor,” he said, “your hero, Gordianus the Finder, started out as a young man living alone with his Egyptian concubine, but over the course of the series, he's become an ideal father. What is that about?”

I had no answer. It was something I'd never thought about. But the man was right. Readers sometimes see patterns in the books that I don't see. I'm like the painter with his nose to the canvas, fussing over details. Gazing from a distance, the reader sees the big picture.

The mute street urchin Gordianus adopted in the very first book, Roman Blood, becomes his beloved sidekick, especially in the short stories in the series. The slave boy Gordianus frees and adopts later causes him no end of grief when he becomes the amanuensis (and possibly the lover) of Julius Caesar. The daughter born to Gordianus and his concubine-cum-wife proves to be as willful as her mother and determined to follow in her father's footsteps, flagrantly ignoring the circumscribed role of women in Roman society. Even as the Roman Republic comes crashing down, Gordianus's primary concern is invariably his children. To protect them he resorts to desperate measures, sometimes betraying his own sense of right and wrong.

I can't say I had an ideal father, and I'm not a father myself. In writing a series of novels over almost two decades, I thought I was exploring the last days of the Roman Republic, getting to know larger-than-life figures like Cleopatra and Cicero, and striving to perfect my mastery of the mystery plot. But all along I was creating an ideal father. And I didn't even know it.

All writing is an act of self-exploration. Even a grocery list says something about you; how much more does a novel say? The so-called literary novel consciously attempts self-analysis, while the genre novel supposedly does not, offering merely—literally—generic entertainment. Don't believe it. Even the crudest, most derivative novel is an expression of the author's hopes and fears and ideas about good and evil. Even the most commercial writer is, at some level, exploring personal demons.

So why do I write? To earn a livelihood, certainly, and I feel lucky I'm able to do that. To say some things about history and human nature. To get a sense of who and where I am in the world. And, apparently, I write because some part of me needed to create an ideal father, even if he exists only on paper and in the minds of those who read my books.

Steven Saylor's novels have been published in 21 languages. The latest is Empire: The Novel of Imperial Rome, forthcoming from St. Martin's Press in September.