Marian Wenzel, who has died aged 69 of cancer, was the world's leading authority on the art and artefacts of medieval Bosnia and Herzegovina; a doughty champion of the Bosnian people during the war waged against them by the Serbian army from 1992 to 1994; and founder director of the charity Bosnia-Herzegovina Heritage Rescue (BHHR).
Born in Pittsburgh, Pennsylvania, Wenzel was drawn to Bosnia by travel books shown to her by a relative. Three years after taking a BA in philosophy at Columbia University, New York, in 1957, she began the research at the Courtauld Institute of Art that, in 1966, led to her PhD. This focused on the form and ornamentation of Bosnian tomb monuments (or stecci) of the 12th-15th centuries - strange, casket-shaped stone tombs thought to have been created by an elusive heretical sect, the Balkan Bogomils, in a curious admixture of central European Catholic, Eastern Orthodox, Mamluk Egyptian and Ottoman Islamic styles.
Fellowships at the Warburg Institute, from 1960 to 1964, led to its then director, Ernst Gombrich (obituary, November 5 2001), employing her drawing skills to illustrate several of his books. On field trips to Bosnia, Wenzel travelled by donkey along the medieval mountain road system in order to sketch the ancient tombs. Her thesis, published as Ornamental Tombstones In Mediaeval Bosnia And Surrounding Regions (1965) established her as the leading scholar in this area of cultural studies.
Her first important step forward had come from a chance meeting one evening in Sarajevo with John Fine, an American scholar of the medieval Bosnian church. Neither had discovered any traces of the influence of the Bogomil heresy in either Bosnian tombstones or church records, so, there and then, they overturned the accepted view by concluding that there was nothing Bogo- mil in medieval Bosnian culture, a finding that Wenzel published in 1962.
She then came to realise that these early Bosnian figurative motifs did not originate with the tombs, but were derived from ornamental silver metalwork: this metalwork, not the tombs, was the most important art form of 14th- and 15th-century Bosnia. The timely exhibition of Masterpieces Of Serbian Goldsmiths' Work, at the Victoria and Albert museum in 1981, crystallised her theory.
With characteristic courage, Wenzel used a lecture at the Serbian Academy of Sciences, Belgrade, to announce her discovery of the significance of the Bosnian metalworking tradition - and that most of the goldsmiths' work displayed in the London exhibition was not Serb, but Bosnian. Unsurprisingly, her lecture (published in 1984) caused a furore, but her ideas were subsequently accepted.
Wenzel searched for Bos-nian metalwork in London auction houses and dealers' galleries. For them, she researched many curious metal objects, including the sinister antique statue of the Horned Man, and she produced numerous publications, most notably her two-volume catalogue of the Khalili collection of Islamic rings (1993).
She never lost sight of the relationship of the artefacts to the lives and ideas of the people who produced and owned them, and, when Bosnia was invaded by Slobodan Milosevic's forces in April 1992, she found herself uniquely well placed to set up BHHR. With the support of its president, Patrick Cormack MP, she campaigned to alert the world to the damage being inflicted upon Bosnia's cultural, historical and natural heritage, and to coax and bully money and publicity from governments and their agencies. Letters and telephone calls poured ceaselessly from her minuscule bedsit.
Wenzel's most important acts came perhaps in the earliest days: the compilation of the first list of war-damaged monuments (1992); the first post-invasion cultural commission to visit Sarajevo, in 1993 (for which BHHR was joined by Roger Shrimplin, of the Royal Institute for British Architects); and many surveys to investigate the state of the principal Bosnian museums - including those in Serb-held areas - commissioned by the Council of Europe. Though she is irreplaceable, BHHR's work continues.
To meet Marian Wenzel was to be struck by her presence and imposing 6ft height, and to be delighted and astonished by the extraordinary range of her knowl edge and the fertility of her ideas. One would gain glimpses of her vivid imagination and spirituality - qualities that found expression in her own paintings and sculptures, her stage and costume designs and her wonderfully theatrical wardrobe (she was a collector of historic dress).
Wenzel always found time to paint and sculpt; even during her most frenetic periods of activity, she would disappear at least once a month to spend a day in the studio of her friend Neil Drury. Her last one-man show, Bosnia: War, Memory And Rebirth, was first shown at Leighton House, London, in 1998, and then travelled around Bosnia.
She leaves a brother and a sister.
· Marian Barbara Wenzel, art historian, artist and campaigner, born December 18 1932; died January 6 2002.