CLARKSON VALLEY — Dean Mandis, insurance executive and father of two students in the Rockwood School District, stood before the district's superintendent and seven School Board members Thursday night at Crestview Middle School. He had three minutes to broach an issue that had been bothering him for a month or so.

Wearing a navy, pinstripe suit with a patterned purple tie and black leather loafers, Mandis adjusted his rimless glasses, took a breath and began.

Mandis' daughter, an eighth-grader, had come home from school recently with evidence that she was being taught something other than the traditional calendar dates of B.C. (Before Christ) and A.D. (Anno Domini, Latin for "in the year of the Lord.")

Instead, her teacher was quizzing social studies students on alternative calendar designations that are increasingly common in higher education — C.E., for Common Era and B.C.E., for Before the Common Era.

"Introducing B.C.E./C.E. in conjunction with B.C./A.D. in the classroom is to deny the historical basis of the dating system and ultimately leads to confusion," Mandis told the board. Mandis said this teacher's decision was "irresponsible" and possibly "a dangerous and slippery slope."

In the hallway outside the meeting, Mandis initially said he was uninterested in the religious issues at stake. But he eventually admitted he wasn't bent out of shape because of an affront to the Gregorian calendar.

"This is a movement that's occurring nationally," Mandis said of the adoption of the B.C.E./C.E. system. "The intention is to secularize our schools and our country."

Thomas Madden, a history professor at St. Louis University and director of the school's Center for Medieval and Renaissance Studies, said the movement to use C.E. and B.C.E. in western academia began in the 1980s and is "much more prevalent" now.

"B.C. and A.D. are references directly to Christ, so B.C.E. is supposed to be more sensitive to non-Christians," Madden said. The idea is that when B.C. and A.D. are not used, "non-Christians don't have to be confronted with numbers that reference Christ's birth."

A similar debate surfaced in Kentucky in 2006 when a staff member at the Kentucky Department of Education proposed substituting the newer designations for B.C. and A.D. in middle and high school social studies classes across the state.

But Christians fought the proposal, and it died before it could be implemented.

"Since our inception, Christianity has played a key role in the formation of our nation, and there's no reason to back away from that reality simply because some bureaucrat authorized a shift," said Kent Ostrander, executive director of the Kentucky Family Foundation, which led the charge against the change.

Last year, former state Sen. John Loudon, R-Chesterfield, filed legislation to make B.C. and A.D. Missouri's "official dating standard," so the state could not "use any other designation."

"It was met with a jaundiced eye," Loudon said. "People said, 'No one's deliberately trying to scrub the calendar of any mention of Jesus Christ.' But, in fact, there is an effort, as evidenced by what's happening in Rockwood."

Craig Larson, Rockwood School District superintendent, scoffed at the suggestion that his teachers are attempting to secularize their students.

"There's no agenda here," he said. "We're just teaching kids how to understand dates."

Last week, Larson reacted to the debate on his blog.

"Within the last 10-15 years, CE/BCE has started to appear in student textbooks, usually along with AD/BC and sometimes with just one or the other mentioned," he wrote. "Teachers make sure that students are aware of both designations so they are literate when they encounter either notation."

Madden said the hypercompetitive textbook market has meant that more publishers are using C.E. and B.C.E. as a way to distinguish themselves as more religiously sensitive alternatives to traditional texts.

Both Larson and Bill Gerling, social studies consultant for the Missouri Department of Elementary and Secondary Education, said there was no official policy on dates.

Gerling said the issue had not come up before, and that curriculum decisions are left up to district officials.

But, he said, "there are all kinds of calendars out there — Jewish, Muslim, Chinese — and if you're going to teach world history, you need to introduce kids to different cultures."

But such reassurances have not calmed some of the district's parents. More than 600 people have signed a petition demanding the continued use of B.C. and A.D., and declaring that the B.C.E./C.E. system "is inconsistent with the traditions and principles upon which our country was founded."

As it happens, foundings and births have been standard pegs for calendar measurements through history. A sixth-century Roman monk is credited with calculating the date of Christ's birth, and a century later, the English monk Bede began tying history to that date. The designations B.C. and A.D. were widely used by the 14th century.

"We have to have some way of measuring the year, and that measurement has to be pegged to something," said Madden. "Most cultures peg that measurement to something important to them."

Ancient Romans used the formation of the city of Rome. Muslims use the hijra, Muhammad's flight from Mecca to Medina in 622 A.D.

Despite the increased use of B.C.E. and C.E., many scholars feel the designation is more cumbersome than traditional dating and is understood by fewer readers. The Chicago Manual of Style, used by many academics, has no preference for B.C.E. or C.E. The Associated Press Stylebook prefers B.C. and A.D.

But the most fundamental problem with the B.C.E./C.E. system is that at its root, the newer system is still a measurement of time based on the birth of Christ. The definition of "the common era" is the 2009 years since.

"Usually it's used to make the person using it feel better about themselves — that they're more sensitive and aware of other people," said Madden. "But it doesn't change what the numbers measure."

On Thursday night, School Board members sat behind a dais decorated with the slogan, "We do whatever it takes for students to realize their potential."

They had listened silently as Dean Mandis expressed his concerns. Then, as someone informed Mandis his three minutes were up, he came to the crux of his argument.

"Our students in the Rockwood School District," he said, "deserve to know what 2009 refers to."