Ensemble Music Society, the Indianapolis chamber music presenter, has cancelled its Feb. 21 performance by the internationally known Guarneri String Quartet at the Indiana History Center due to illness.

John Dalley, the Guarneri's second violinist, has taken a leave to undergo cancer treatment, according to Ensemble Music Society president John Failey. Failey said the Ensemble Music Society board of directors will decide issues including whether a replacement ensemble will be chosen and what the procedure for tickets will be.

Founded in 1964, the Guarneri is one of the best-known string quartets in the world. It had already announced plans to retire after the 2008-09 concert season.

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