Leaders of one of the Catholic Church's largest orders of teaching brothers, trying to create an $11 million retirement cushion for its members, are selling developers parcels of land on a historic 400-acre tract in Prince George's County that the religious order has owned since the 1880s.

The Christian Brothers estimate that they will need the money from the sales to invest in a pension, health and retirement fund to care for the 120 brothers in the order's southern province who are now over 60.

As the centerpiece of the ambitious business park, a developer has asked county zoning officials to change the present residential zoning of 50 acres surrounding the Christian Brothers' 100-year old Ammendale Normal School and seminary grounds in Beltsville so that the buildings can be restored and refurbished into a 200-room conference center and hotel. The school and its surrounding acreage are listed on the National Register of Historic Places.

Under the same proposal, up to 450,000 square feet of space in office buildings would line both sides of the stately, tree-lined drive leading to the monks' former school and residence.

"We are looking at a total project investment of at least $50 million, including the land," if the zoning is approved later this year, as expected, said Anthony R. Manganaro, president of Siena Corp., the Columbia development firm that has an option to buy the four-story, 1885 Christian Brothers monastery and about 50 acres.

Under the Siena plan, about 18 retired brothers would continue to live at nearby La Salle Hall, the former seminary's high school, and St. Joseph's Parish Church would be reconstituted as a nondenominational chapel for use by conference-center guests and the adjacent business community.

Manganaro said that if he cannot get a commitment from different companies to take 50 percent of the conference center space when it is completed, Siena will turn the eclectic Victorian structure into executive office suites.

In the last two years, the Christian Brothers have rezoned and sold about 200 acres of the 400-acre parcel for a gross income of $5.2 million, said Joseph Anastasi, a development specialist with Kenneth H. Michael Cos. Inc., the firm the religious order hired to develop and market the property.

"The Christian Brothers are doing what every religious order in the U.S. is doing -- building a pension fund," Anastasi said. "They've got a whole lot of old men, and they have to start thinking about what to do with them."

Brother Gabriel Cannon, who first came to the site 60 years ago as a seminarian of 15 and now serves as the order's retirement director, said, "There are still several properties to be sold, and we hope to generate about $11 milllion to invest in our pension program."

To date, most of the money -- about $3 million in land-sale revenues -- has been plowed back into direct costs entailed in creating drainage areas, and bringing sewer, water and utilities to the office sites or improving and building roads, Anastasi said.

"So far, the brothers have put less than $1 million in their pockets . . . . First they had to get the zoning and then make these lots buildable," Anastasi said.

In addition to the 50 acres that Siena hopes to develop, 180 acres of the 400-acre tract are already part of one of the county's largest business parks, the Ammendale Business Campus, a collection of offices that is designed to attract large employers to the area just north of the Capital Beltway, while upgrading the down-at-the-heels image of Beltsville's adjacent old industrial strip along Rte. 1.

Several firms, which carved off parcels earlier, are already fully operational in the distribution centers, research and development facilities and corporate headquarters they built around the seminary grounds.

Ritz Camera Centers Inc. was the first of several nationally known firms to locate its corporate headquarters in the Ammendale business park after investing $4 million in land and building materials to construct a 75,000-square-foot showroom and distribution center, said President David M. Ritz.

"We put up the first facility, and I think our place had the architectural look which said, 'This is not just another, run-of-the-mill warehouse distribution center.' " Ritz is the nation's largest retailer of photographic and video equipment, with 180 stores, 14 of which are in the Washington area, he said.

In addition to the Ritz property, Micros Business Systems, James A. Cassidy & Co., which distributes building components, and Com-Site International, which designs and builds computer rooms, have built headquarters on property they bought from the Christian Brothers along Rte. 1. The buildings range from 45,000 square feet to 95,000 square feet, Anastasi said.

Bray & Scarff, retailers of large household appliances, is currently constructing a 45,000-square-foot distribution facility that also will serve as its corporate headquarters. Arnell Developers of Bethesda is putting in four buildings with a total of 160,000 square feet of speculative research and development space that Arnell will lease.

Rouse & Associates has completed the first of three construction projects that will total about 500,000 square feet of space in 10 speculative office buildings, said Rouse project manager Mark Dishaw.

Dishaw said Rouse bought the first parcel in March after looking at the property "for well over a year . . . . The Christian Brothers land is very beautiful, and at first we weren't sure there was a market for quality development in this area," Dishaw said. "But our pioneering has paid off and the buildings are 77 percent leased."

Dishaw said Rouse paid $3.5 million for 31 acres, seven of which are in a floodplain which the brothers did not charge the company for.

Siena's Manganaro agrees that Beltsville's image leaves something to be desired. "Right now, driving south on Rte. 1 is like being on the Bataan Death March . . . the place looks like skid row. But the Christian Brothers site set back on the north side of Rte. 1 is like another place on earth, another century . . . it is pristine and serene."

Manganaro said his development proposal has the support of the Christian Brothers, county officials and state and national historic preservation proponents "because they know we intend to restore the buildings and keep the 26 acres of historic grounds immediately surrounding the brothers' home as is."

Manganaro said he believes development of the historic site will act as a catalyst for the "down and dirty Beltsville area" and improve the image of the county. He said Prince George's County Executive Parris Glendening has promised to widen Powder Mill Road to Ammendale Road and said "that will give us a direct connect to I-95 from the Calverton exit and allow us to avoid Rte. 1 all together."

The Christian Brothers have been a fixture in the county since the teaching order acquired an original 25-acre site for $400 in the late 1870s from Civil War Adm. Daniel Ammen, a childhood friend of President U. S. Grant.

The order moved its seminarians from Baltimore to a healthier site in the country with the completion of the ornate Queen Anne novitiate building with its brick patternwork in 1880 at a cost of $30,000, according to records kept by the order and county historians.

The brothers taught local children along with seminarians in a self-sufficient farm community that boasted its own bee hives, vegetable garden, poultry and pigs as well as ice house, root cellar, orchards and vineyard.

In 1889, the order purchased the adjoining Drury Mansion for $16,800, and later the 100-acre Hoban farm for an undetermined price.

In 1968, the last class of seminarians graduated and La Salle Hall became home to the retired brothers. In 1975, the original gingerbread Queen Anne seminary and high school buildings and 26 surrounding acres were named to the National Register of Historic Places.

Besides operating St. John's Military Academy in Washington, the order teaches in diocesean schools throughout Maryland and runs La Salle College in Baltimore.

"The way we originally acquired these lands was very fortunate, very providential. Many parcels were gifts and now their sale is the only source of revenue for our retirement," Brother Cannon said.