Klaus Mertens and consistency, Klaus Mertens sang in every piece that required a bass soloist, 190 in all." He is also involved in the project Dieterich Buxtehude – Opera Omnia of the same ensemble to record the complete works of Dieterich Buxtehude, begun in 2005. As a singer of lieder, he has interpreted songs of Claudio Monteverdi, Antonio Caldara, Wolfgang Amadeus Mozart and Franz Schubert among others. He has performed the title roles of the romantic oratorios "Elijah" and "St. Paul" by Mendelssohn and, as music of the 20th century, Paul Hindemith's "Requiem" and Igor Stravinsky's "Oedipus rex". In the classical repertory
St. Elijah Cathedral, Haifa Akka was the church of the Virgin Mary in Haifa. After the Arab-Israeli war (between 1947-1949), most Melkites, who lived in the area, moved to the lower city of Haifa,and the bishop's chair was moved to the church St. Elijah (St. Elias). The front of the cathedral is crowned with a cross, which is a few meters away from a small bell tower. On the portal is the biblical story of the prophet Elijah. St. Elijah Cathedral, Haifa The St. Elijah Cathedral (, ) also called St. Elias Greek-Melkite Cathedral, is the name given to the Melkite cathedral in Haifa,