Warren Alfred Peterson, an architect and founding partner of one of the most highly regarded design teams in 20th-century Baltimore, died March 21 of complications from pneunomia in Jamestown, N.Y. He was 81.

With Charles Brickbauer, Mr. Peterson in 1963 established Peterson and Brickbauer, a small but influential partnership whose buildings for corporate, institutional and residential clients gained attention and praise far beyond Maryland.

Its legacy includes the former headquarters of Blue Cross and Blue Shield of Maryland, a mirrored-glass cube in Towson; the former Sun Life Insurance Co. and Mercantile Safe Deposit and Trust Co. headquarters in Baltimore's Charles Center; the former Baltimore City Life Museum's exhibition center with its "folded" cast-iron facade, and the soaring passenger terminal at what is now Baltimore- Washington Thurgood Marshall International Airport, built in 1979.

One of its buildings, the former Bankers' Trust tower in lower Manhattan, was damaged during the terror attacks of September 2001 and had to be dismantled.

During a career that spanned more than 40 years, Mr. Peterson worked with clients ranging from former Orioles pitcher Jim Palmer to arts patron Edith Hooper to inventor Howard Head. His institutional clients included the Bryn Mawr School in Baltimore; Washington College in Chestertown, Bennington College in Vermont and the University of Colorado.

Operating from 1963 to 1994, Peterson and Brickbauer developed a reputation among colleagues and competitors as one of the best design firms in Maryland, with a studio atmosphere that made it a valuable training ground for young architects.

"It was a great team," said M. Jay Brodie, president of the Baltimore Development Corp. and an architect by training. "They were the cutting edge of contemporary architecture when they were working together. I have always admired their designs. It was a wonderful partnership."

"They certainly blessed Baltimore," said architect David Wright, who competed against them for commissions. "The talent that they brought to the Baltimore landscape was phenomenal."

Martin P. Azola, a developer and client said, "Many of the best buildings in town were theirs."

"We all knew that we were working for two of the best," said Sharon Miller, an administrative assistant for Peterson and Brickbauer during the 1970s.

Born June 3, 1928, in Jamestown, N.Y., Mr. Peterson attended public schools and graduated from Jamestown High School in 1946. His father, Sven, was an upholsterer. His mother, Ethel, was a homemaker. Growing up, he loved to socialize and was good at it. In his later years, with thick white hair and a cane, he was a colorful character who looked a bit like a Southern senator or Col. Harland Sanders of fried-chicken fame.

"Warren was a romantic who loved the things that high society loved," said Cal Correll, the first employee of Peterson and Brickbauer. "He hobnobbed with high society. He could talk to anybody."

According to a sister, Shirley Raymond of Jamestown, Mr. Peterson displayed a talent for drawing buildings at an early age and always wanted to be an architect. He studied architecture at Yale University, where he received a bachelor's degree in 1952 and a master's degree one year later.

In 1953, Mr. Peterson was named a Fellow of the American Academy in Rome, where he lived for two years as a recipient of the Rome Prize in Architecture. Returning to the U.S., he worked with the renowned architect Pietro Belluschi on designs for the Bennington College Library in Vermont and the Pan-Am Building in New York.

Mr. Peterson moved to Baltimore in 1960 to work for Meyer and Ayers, where his projects included an administration building for the University of Colorado in Boulder, the Thomas and Hugg building for the Maryland Historical Society, and the Sun Life tower in Charles Center. He had been recruited with the promise that he would be named a partner at Meyer and Ayers. But when that did not happen, he opened his own firm, taking the Sun Life commission with him.

With a downtown office building as his first project, Mr. Peterson realized he needed a partner and contacted Mr. Brickbauer, also a Yale graduate and Rome Prize winner.

"Warren's great flair was his understanding of traditional architecture," Mr. Brickbauer said. "He had great strengths there."

The partnership was fortunate to receive major commissions from the start. They were selective in the projects they took on and kept the staff relatively small to focus on design, letting associate firms such as Emery Roth & Sons produce the construction documents.

"They didn't chase little things to fill the day," said Mr. Azola, who worked with Peterson and Brickbauer on the Devon Hill condominiums and several downtown buildings.After Sun Life was under way, Peterson and Brickbauer teamed with British-American Properties and won a competition to build the 21-story Mercantile tower in Charles Center. Those projects led to morecorporate commissions, including the Blue Cross building in Towson, which was published internationally, and the Bankers' Trust tower in Manhattan.

"Sun Life was the lucky thing," that launched the office, Mr. Brickbauer said. "There were just the two of us, with Emery Roth backing us up."

Another coup was being hired in the 1970s to design a new airport terminal for the state of Maryland, which wanted to upgrade the 1950s-era Friendship Airport. The terminal, known for its airy space frame ceiling and red-tile columns, has helped BWI to be consistently rated as one of the country's most attractive and traveler-friendly airports.

Other major commissions included the green glass headquarters in Mount Washington for F&G; Life (now home of the DLA Piper law firm), and buildings for the Baltimore City Life Museums, including an exhibition center made with pieces of the cast-iron facade salvaged from the old G. Fava Fruit Co., folded like an accordion to fit onto the site.

Peterson and Brickbauer were equally adept at adapting old buildings as designing new ones, said Hugh McCormick, the company's last employee. The two principals "both had traditional training and a strong historical perspective from being at the American Academy in Rome. Their modernism was reflected through the eyes of history. ... They just had a sensibility about architecture as a grand art."

They didn't take on too much work at once, and that helped keep quality high, said David Kerivan, who worked for Peterson and Brickbauer and later in association with Mr. Peterson. "They treated each one as if it was their only project, which allowed the quality of the design to come through," Mr. Kerivan said.

At the end of 1994, Peterson and Brickbauer dissolved their partnership. Mr. Brickbauer became aligned with another design-oriented firm, Ziger/Snead. Mr. Peterson continued to work on residential commissions, often in association with Mr. Kerivan.

In his free time, Mr. Peterson, a longtime Homeland resident, enjoyed boating and traveling, including trips to Bermuda.

By 2005, Mr. Peterson's health was failing and he moved to an assisted living facility in Jamestown. In addition to his sister, survivors include a niece and a nephew. A private service was held Friday.