In an obituary in Friday's editions of The Washington Post about Jan Henryk de Rosen, 91, a painter of religious murals who died of cancer Aug. 22, the name of a surviving sister was misspelled. She is Marie Wszelaki of Arlington. The obituary also should have made clear that Mr. de Rosen never visited the Soviet Union although some of his paintings are in what is now Soviet territory.

Jan Henryk de Rosen, 91, a painter of religious murals, a soldier in three armies during World War I and a former diplomat in the service of his native Poland, died of cancer Aug. 22 at Northern Virginia Doctors Hospital.

Mr. de Rosen did paintings in the Washington Cathedral, St. James Lutheran Church and other churches in this area and elsewhere in the country, and an enormous mosaic in the National Shrine of the Immaculate Conception. From 1939 to 1949, he was a research professor of liturgical art at Catholic University. Although art became his life's work, he once said he had resisted becoming an artist.

A native of Warsaw, Mr. de Rosen grew up in France and attended the universities of Paris and Lausanne, Switzerland . His father, Jan de Rossen, was a court painter for Czar Alexander III and Czar Nicholas II of Russia and would travel from his Paris home to St. Petersburg to receive commissions.

When World War I broke out, Mr. de Rosen joined the French army. He later served in the British army and finally in the newly constituted Polish army, in which he became a captain. From France he received the Croix de Guerre and the Legion of Honor; from Britain, the Military Medal, and from Poland, the Cross of Valor, the Cross Virtuti Militari and the Gold Laurel.

When the war ended, Mr. de Rosen became a diplomat for Poland, then in the glow of its first full independence since the 18th century. He was a translator during the peace negotiations at Versailles and elsewhere.

In the early 1920s, he returned to Poland. He spent 1924 on the estates of an uncle and there, at the age of 33, he began to paint. The next year, when he showed his paintings in Warsaw, his works were sold out overnight.

"I did not want to be a painter but I could not help myself," he once said.

Mr. de Rosen's first major work, the murals in the Armenian Cathedral in Lwow, Poland, was completed in 1929. He later was commissioned by Pope Pius XI to paint four murals in the pope's private chapel at his summer palace in Castel Gandolfo.

In 1937, Mr. de Rosen came to Washington to visit friends and was asked to do paintings for the Polish pavilion at the 1939 New York World's Fair. Two years later he was commissioned to paint the mural entitled the "Entombment of Christ" in St. Joseph's Chapel at the Washington Cathedral.

During World War II, he served as a military and intelligence aide in the Polish Embassy. He remained in this area for the rest of his life.

In the early 1950s, Mr. de Rosen did a painting with gold leaf at St. James Lutheran Church in Northwest Washington. Then, in 1959, he completed what was then the largest figure of Christ in mosaic, pieces of tinted glass that covered 3,610 square feet of a curved stone surface, at the National Shrine of the Immaculate Conception.

Mr. de Rosen also created what is believed to be the largest mosaic in the world, 14,000 square feet, which covers the dome of the St. Louis Cathedral in St. Louis.

Other works by him in this area are paintings at St. Agnes Episcopal Church, St. Matthew's Cathedral, and the headquarters of the U.S. Catholic Conference. He also did murals and mosaics in Austria, Italy and the Soviet Union. At the time of his death, he was working on a picture at his studio on F Street NW for a church in Pittsburgh.

Mr. de Rosen, who lived in Arlington, had what he called an "absolute abhorrence of games and sports," but said that running up ladders and scaffolding kept him in good trim.

In 1978, he was inducted into the Papal Order of St. Gregory the Great and awarded the Commander's Cross. He was a member of the Polish American Arts Association and of the Polish Veterans Association.

He is survived by a sister, Marie Wszelki of Arlington.

"Religious art requires a lot of knowledge," Mr. de Rosen used to say. "The trouble today is that people do not have the slightest understanding of the tradition and meaning behind what they are painting . . . Painting is about the same process as writing. It requires great concentration and discipline."

And, he added, "I paint my murals with wax colors dissolved in water. They do not fade, but, like most of us, mellow with time."