David Baroody stood up at a recent introductory meeting at Briar Woods High School in Brambleton to invite other parents to attend the new school's first football game.

He made sure to emphasize who the school's Falcons would be playing: the Eagles of the new Freedom High School in South Riding.

Four years ago, Baroody was part of a group of parents who argued the Brambleton school should be built before the South Riding school. He maintained that there would not be enough students to fill two schools this year and that building both at the same time would waste money and compromise students' educations. Parents in South Riding argued just as vocally that their school should be built first.

Now, Baroody said school administrators have convinced him that the academics and extracurricular activities at both schools will equal those at Loudoun County's eight other high schools. The once-gripping debate that divided the two communities has mellowed into a respectful sports rivalry, he said.

"At the end of the day, I'm very excited," said Baroody, president of Briar Woods' music booster club. "My concern at the time was that it might cause harm from an educational standpoint. That did not bear out, and that's good news."

In most counties, the opening of a high school is a once-in-a-generation event. Loudoun County, with its explosive growth, has opened four since 1997. Still, opening two high schools at the same time -- each with room for as many as 1,600 students -- is unprecedented in Loudoun, not withstanding the pace of construction here, and represents the conclusion of a bruising and divisive debate.

Both sides now say they are thrilled with their schools and ready for the start of school. The principals said that as of Thursday, 460 students in ninth through 11th grade had registered at Briar Woods and 550 at Freedom, numbers expected to rise.

They join more than 46,000 other Loudoun students who start classes tomorrow, a 7.8 percent increase over last year.

Three new elementary schools -- Legacy, Newton-Lee and Pinebrook -- also open tomorrow, all in fast-growing eastern Loudoun.

Cheryl Bacak, a South Riding parent who lobbied for a school to be built there first -- and then embraced building both at once as a compromise -- said the numbers show that both communities are growing at roughly equal rates and will need all the classrooms soon. "There was so much controversy, but both schools are necessary," she said.

School Board Chairman John A. Andrews II (Potomac), who had argued that growth did not support building both schools at once, said he was less sure now. Still, he said increased fuel and steel costs are causing construction costs to increase sharply each year, so that building both sooner may have been the wisest choice after all.

"It's pretty much a break even," he said. "I wouldn't be surprised if we saved a little money by building them at the same time."

School system projections show both schools growing steadily the next five years. The opening day enrollment for the two schools, however, makes them the smallest county high schools in decades.

Principals Edward Starzenski at Briar Woods and Christine Forester at Freedom both said students will be able to take the same classes offered in their grades at any other school.

Five courses, including an AP calculus course and AP psychology, will be taught jointly at the schools, using distance-learning software in which students at one school watch a teacher at the other school on a monitor.

"Everything students asked for is being offered," Forester said. "That was a commitment we made to students."

The hardest part of opening both schools at once, she said, was hiring teachers and coaches. At times, the schools were pursuing the same teachers, she said. The schools are only miles apart, so both principals knew the commute was unlikely to be a consideration for prospective hires and did their best to woo candidates.

"We're all out there looking for the same kind of people, and we all want the best," Forester said.

Parents in both communities said they were pleased with the teachers who had been hired. They have been flocking to orientation events and weekend festivals to learn more about the schools. Home builders and real estate agencies in the two neighborhoods have been donating money to show support.

Forester said the schools were pumping Friday's game between the Falcons and Eagles, in hopes both communities will come out. "It's going to be the battle of the birds, to find out who rules the nest," she said.

About 550 ninth- through 11th-graders will attend Freedom High School.