Ilona Mathe Boissenin, 66, a homemaker who, before the collapse of the Soviet Union, was an advocate for Hungarians living behind the Iron Curtain, died Oct. 31 of lung cancer at Capital Hospice Inpatient Center in Arlington. She was a longtime Annandale resident.

Mrs. Boissenin was born in Riska, Transylvania, in Romania. In fall 1944, in the company of her parents, three sisters and a brother, she fled her home, then in Hungary, in advance of invading Soviet and Romanian armies. Two brothers and a sister were left behind. She spent five years in several British-operated displaced persons' camps in Austria.

In 1950, she and her parents immigrated to the United States under the sponsorship of the Unitarian Church of Wilmington, Del. She became a naturalized citizen in 1956.

She attended Washington College from 1956 to 1959, the year she married U.S. Navy Ensign William Charles Boissenin. As a wife of an active-duty Navy aviator and the mother of four children, she established and maintained homes in seven cities before settling with her family in Annandale in 1975.

Cut off for almost 30 years from her siblings, who remained in Hungary and Romania, she became an ardent advocate for people living behind the Iron Curtain, particularly in her native Transylvania, a Romanian province that, in times past, has been claimed by Hungary. During the 1980s, she represented the Transylvanian World Federation, testifying before several congressional committees in opposition to "preferred nation" trade status for Romania because of its mistreatment of the Transylvanian minority in its midst. She also was able to reunite with two of her sisters who had remained in Europe.

Survivors include her husband of 45 years, of Annandale; four children, Felice DeSautelle of Rochester, Minn., Cynthia Albee of Dillon, Colo., Eugene Boissenin of Savannah, Ga., and James Boissenin of Annandale; three grandchildren; and four sisters and a brother.