Bass-baritone Klaus Mertens is a leading singer of Baroque concert repertory, especially the music of Johann Sebastian Bach. He has recorded nearly 100 of the cantatas and all the large choral works of the Leipzig master to great acclaim.
He was given singing lessons while in elementary school. His university studies were intended to prepare him for a career as a music teacher, and he worked as a schoolteacher for a time. But his developing vocal talents made it feasible to attempt a serious singing career. He embarked on additional voice training, teaching, and interpretation studies with Else Bischof-Bornes, Jakob Stämpfli, and Peter Massmann.
Since much of the activity in the early music field is associated with summer music festivals, he frequently appears at such venues as the Lucerne Festival, the BBC Proms, the Mostly Mozart Festival of New York, the Salzburg Festival, the Prague Spring, Bach-Tage Berlin, the Flanders Festival, the Oxford Handel Festival, and many others.
In common with many other early music specialists, Mertens also has an interest in major repertory of the 20th century, performing Hindemith's A Requiem for Those We Love and Stravinsky's Oedipus Rex, among other works. He has also received praise for his work in Mendelssohn's Elijah, the same composer's Paul, and other major Romantic concert works. He also is highly regarded as a lieder singer. Mertens has frequently appeared on European television and radio broadcast concerts.