PROVO — Educated as a boy in Catholic parochial schools in Buffalo, N.Y., John Colletta is apt to apply religious terminology when addressing an audience of mostly Mormon genealogy enthusiasts about the potential pitfalls in writing a narrative family history.

"I remember to this day very well that there are sins of commission and sins of omission," Colletta said Wednesday. "According to the Catholic catechism, you can sin by doing something, and you can sin by neglecting to do something. Well, ladies and gentlemen, I hate to shock you here at Brigham Young University, but I have to tell you, when it comes to writing narrative family history, Catholic doctrine applies."

Colletta was the second-day keynote speaker at the four-day annual Conference on Family History and Genealogy being held at the university through Friday.

Coletta is a nationally known lecturer and author who taught genealogy at the National Archives and Smithsonian Institution for 21 years.

In his lecture, he warned would-be authors to beware of 10 snares, including:

Anachronisms — In his own published narrative family history, "Only a Few Bones," about a catastrophe that happened to his mother's family in Mississippi in 1873, Colletta did careful on-site research.

Based upon that, he sought to recreate a courthouse scene in Vicksburg, writing about the starlings poking in the rain-saturated lawn outside the building.

An e-mail from a reader of the book, an ornithologist, alerted him to the fact that there were no starlings in Mississippi in the 1870s; they were not imported from England until the 1890s.

"When you write a narrative family history, you're confronted with thousands of bits of information," he said, "thousands of facts that you want to document and make sure they're accurate."

Inappropriate historical association — "This is when you pair an event in an ancestor's life with another, more famous, known historical event of the same time," he said.

Intending to give the narrative a historical context, some authors err in inserting an event that is totally unrelated to it, he explained. Noting that a back-country Kentucky resident was born the very day that Victoria was crowned queen of England does not work, he said, by way of example.

Glib generalizations ?— This he identified as attributing generalizations to specific ancestors. For example, he spoke of his Italian grandmother. One might be tempted to conclude from stereotypes that she was always wanting to feed people. But he knew from extensive association with her that she did not like to cook — it messed up her kitchen — and she never touched wine.

Presentism — "It's exploring the lives of your ancestors with a 21st century viewpoint or mentality," Colletta explained. "Your chore as the family historian is to get back into that time and place, get into the mentality and evaluate the sources you have in light of that time and place."

Unfounded assumptions — "It's really easy to misread history," Colletta observed, "because it's easy to read history and find in that text what we expect to find. We think we know history."

As an example, he spoke of a PBS special about Andrew Jackson.

"I cringed and rolled over on my floor every time they showed the White House and the showed the portico that wasn't there when he was president," he said. "Every time they showed the U.S. Capitol building, they showed it with the dome that wasn't there before 1863. It drove me crazy. I kicked in the TV set, and now I have to buy a new one."