The fight for classical music in a place where both government funding and freedom of expression are under threat.

The sun is beating down on me and traffic roars as I trudge uphill past one scaffolding-flanked mosque and sweaty fruit vendor after the next. But my spirits are lifted by the sound of the muezzin call to prayer, ringing out on loudspeakers over the smoggy blue skies of Istanbul. (I felt somewhat deflated when I discovered that they tend to be pre-recorded these days.) Later that night, I would descend the same hill to hear Turkey’s premier orchestra and an international cast in a concert performance of Verdi’s grand opera Aïda — a rare event in Turkey, and certainly not pre-recorded.

The Borusan Istanbul Philharmonic Orchestra presents one opera a year in memory of the famed prima donna Leyla Gencer (1928-2008), a contemporary of Callas who sang the title role of Aïda at La Scala in 1963. ‘La Diva Turca’ inspired a generation of musicians at a time when her homeland was forging its fledgling classical tradition. A mural-sized image and video footage of Gencer, in costume as Verdi’s Ethiopian princess, loomed large over the performance at the Istanbul’s...