HE was born a century ago today in a tenement and grew up to be one of the greatest musicians of the twentieth century, earning a star on the Hollywood Walk of Fame, but he remains almost unheard of in his home country.

He was described by Yehudi Menuhin as ''the first star of the viola'', was a soloist with the world's leading orchestras, and some of the most prominent composers of the century - including Benjamin Britten and Bela Bartok - wrote new works for him.

But in Glasgow, and indeed Scotland, the name William Primrose is unlikely to raise even a flicker of recognition.

Given the extraordinary reputation he earned and his position in musical history, Primrose should be one of Scotland's most famous sons. He was responsible for transforming the maligned viola into a virtuoso instrument in its own right, and was invited by Arturo Toscanini to join the prestigious NBC Symphony Orchestra in New York.

When he died in 1982 in Provo, Utah, Primrose had cemented his international reputation as the greatest exponent of the viola who ever lived.

His story began on August 23, 1904, at 18 Wilton Drive, a small street of tenements in Glasgow's west end behind Maryhill Road. At the time the street was so heavily populated by musicians that it was nicknamed Harmony Row.

John Primrose, William's father, was a violinist in the Scottish Orchestra, now the Royal National Scottish Orchestra, and also taught the instrument at the family's home.

When William was only four years old, his father bought him a quarter-sized violin and, by the time he was 12, he had made many concert appearances in Glasgow. Three years later he moved to London when Sir Landon Ronald, the conductor of the Scottish Orchestra, heard him play and declared him a genius.

Although he received a gold medal, the Guildhall School of Music's highest honour, he later admitted he hated his time there and regularly skipped lessons. Primrose secretly preferred the viola - which was then held in poor esteem - to the violin and in 1926, when his career as a professional violinist began to falter, he went to Belgium to study with Eugene Ysaye, who persuaded him to put aside his violin in favour of the viola.

In his memoirs he described the move as a life-changing experience. He wrote: ''I had become a violist full-fledged. I had burned all my bridges. I had walked the Damascus road, seen the light, repented of past transgressions and turned to the viola.''

He toured Europe, playing in London, La Scala in Milan, and Berlin, before being asked by the legendary Toscanini to join the newly-formed NBC Symphony Orchestra in New York. In 1939 NBC even invited him to form the Primrose Quartet.

After the second world war, his career took off and he played with the Baltimore, Boston, Chicago, Kansas City, Los Angeles, Minneaopolis, Philadelphia, St Louis and Utah symphonies, as well as with orchestras throughout Europe.

In 1953, he was made a CBE and in the following decades turned his hand to teaching viola at the University of Southern California, Indiana University and the Tokyo University of Fine Arts and Music.

Some of the twentieth century's greatest composers wrote music for him, which included Bela Bartok's viola concerto, Darius Milhaud's second viola concerto and Benjamin Britten's Lachrymose. Diagnosed with cancer in 1977, he continued to teach until his death in 1982 in Utah, where he taught at Brigham Young University for three years.

Primrose earned a star on the Hollywood Walk of Fame, but it was not until 16 years after his death that his home city gave him modest recognition with a plaque outside the tenement where he was born.

James Durrant, one of Scotland's leading violists, said: ''I first heard him when I was 14 during the war. I had never heard playing like it. Later, when I was in orchestras in my twenties I played at close quarters to him and it was awe-inspiring. He is the finest string player to come out of Scotland ever and I can't think of anyone at all on that level that's come out of Britain, except perhaps Jacqueline du Pre. It is sad that he is not widely known.''