Earlier this year, Keith Cochran got a call from a friend who saw a sign on the front door of the 155-year-old St. Mary's Academy building. It read: "Notice of intent to demolish."

"I couldn't believe it," said the Lawrenceville architect, who immediately set out to nominate it for historic status, which protects buildings from demolition.

Its fate will depend on whether the city planning commission and, ultimately, City Council deem it a religious structure. If they do, it may have no salvation. The intent and legal meaning of "religious structure" will be parsed on Tuesday, when the planning commission considers the nomination.

The building's owner, the Catholic Cemeteries Association of the Diocese of Pittsburgh, is expected to provide documentation of its use.

The association is challenging Mr. Cochran's right to nominate it because city law states that a religious structure can only be nominated by its owner. The wording has led to confusion.

The Greek Revival brick building that preservationists call "a gem" was built in 1853-54 as a church and a school. It is one of a few Greek Revivals left in the city. Wooden partitions that signified separate classrooms were removed for Mass on Sundays, but the building was too small as the parish's largely Irish population mushroomed.

It became a private girls' academy after a larger school was built, serving as such until 1894, when the parish priest closed it to prevent class-consciousness in the parish. It later served as a home for priests and, in 1920, became a commercial high school.

The Catholic Cemeteries Association bought it and the adjacent church a year ago, intending to raze the academy and convert the church to a chapel mausoleum.

"To force us to keep [the academy] and maintain it would require us to devote resources we don't have," said Annabelle McGannon, executive director of the association.

If the nomination goes through planning and City Council, she said, "our intention is not to put any resources into it. We would much rather have someone buy it."

Defending his nomination, Mr. Cochran said, "We have to somehow get more preservation-minded in Pittsburgh. There has to be a different direction for the good of the city. When I have architect friends visit from out of town, this is a building I show them. These are the kinds of buildings that make people want to see your city."

Because of its role in the formation of a parish and of Lawrenceville, architectural historian Carol Peterson called it "one of the most important Greek Revivals in Pittsburgh."