Bass-baritone Klaus Mertens is celebrated by the press for his "unique expressiveness, his pleasant timbre, his sensitivity for words as well as his convincing music-making" and for being an "excellent master of his Fach". "His interpretations of songs, cantatas and oratorios set standards." Klaus Mertens’ unique characteristic is that he is the only singer worldwide to have sung and recorded the entire vocal oeuvre of both JS Bach and Buxtehude. These recordings, directed by Ton Koopman, continue to enjoy the highest international recognition.
As "one of the leading Telemann singers of our time", Klaus Mertens was awarded the Telemann-Preis of the city of Magdeburg in 2016. "As the ideal conveyor of Bach’s cantatas and passion texts…" he received the renowned Bach-Medaille of the city of Leipzig in 2019.

Reine-Marie Verhagen studied the recorder with Pieter van Veen and Walter van Hauwe and graduated in 1976. She is a regular member of the Amsterdam Baroque Orchestra, conducted by Ton Koopman. With the ensemble La Sfera Armoniosa conducted by Mike Fentross she performed several 17th century operas. For the past 10 years she has also regularly performed 17th-18th and 20th-century music in San Francisco, Amherst, Boston, and New York.
Verhagen takes keen interest in the contemporary repertoire. For the Steve Reich festival at the Royal Conservatory at The Hague in December 2003, she made a very successful transcription of his Vermont Counterpoint for solo recorder and an 11-member recorder ensemble. This composition was also performed in October 2007 at the International Minimal Music Festival in Kassel, Germany, in combination with the premiere of a new minimal composition, written for Reine-Marie Verhagen, by Ulli Goette: “Mural”.
Not confining herself exclusively to musical performance, Reine-Marie Verhagen was a co-founder and former member of the board of the Dutch branch of the ERTA

Ton Koopman founded the Amsterdam Baroque Orchestra in 1979. The group consists of internationally renowned baroque specialists who meet up several times a year and work together to prepare and perform new exciting programmes. For the musicians each concert is a new experience and Koopman's boundless energy and enthusiasm are a sure guarantee of the highest quality.
The Amsterdam Baroque Choir was founded in 1992 and it made its debut during the Holland Festival of Early Music in Utrecht performing the world première of the Requiem (for 15 voices) and Vespers (for 32 voices) by H.I.F. Biber. The recording of both of these works won the Cannes Classical Award for the best performance of 17th/18th century choral music. For its rare combination of textural clarity and interpretative flexibility, the Amsterdam Baroque Choir is considered among today’s most outstanding choirs. In 1994 Ton Koopman and the Amsterdam Baroque Orchestra & Choir embarked upon the most ambitious recording project of the last decades: the integral recording of Bach’s secular and sacred cantatas. For this extraordinary project Koopman and his ensemble received the Deutsche Schallplatten-Preis Echo Klassik. Next to the CD recordings three books have been edited and published by Ton Koopman and the musicologist Christoph Wolff and a series of six documentaries was produced and broadcasted by various TV stations.
Alongside Bach’s music the Amsterdam Baroque Orchestra & Choir has recorded all major baroque and classical works. Major recognitions include the Gramophone Award, Diapason d'Or, 10-Repertoire, Stern des Monats-Fono Forum, the Prix Hector Berlioz and two Edison Awards. In 2008 the ensemble and Ton Koopman have been honoured with the prestigious BBC Award. Since March 2003 “Antoine Marchand”, a new sub-label of Challenge Classics, took over the release of Koopman’s new recordings and among many others has published 22 CD boxes of the Bach Cantatas, a new recording of the St. Matthew Passion (on CD and DVD) and St. Markus Passion of J.S. Bach (DVD), live recorded in Milan, as well as the first seven volumes of the Buxtehude Opera-Omnia Edition. Ton Koopman and the ABO & ABC are regular guests at the major concert halls of Europe, the USA and Japan. In the 2008/09 season they will tour extensively in Europe (Amsterdam, Paris, Madrid, Vienna, Milan, Cologne, Dresden, Düsseldorf etc) and in Far East with concerts in Hong Kong, Seoul and Tokyo.

Ton Koopman was born in Zwolle in 1944. After a classical education he studied organ, harpsichord and musicology in Amsterdam and was awarded the Prix d'Excellence for both instruments. From the beginning of his musical studies he was fascinated by authentic instruments and a performance style based on sound scholarship and in 1969, at the age of 25, he created his first Baroque orchestra. In 1979 he founded the Amsterdam Baroque Orchestra followed by the Amsterdam Baroque Choir in 1992.
Koopman's extensive and impressive activities as a soloist, accompanist and conductor have been recorded on a large number of LPs and CDs for labels like Erato, Teldec, Sony, Philips and DG, besides his own record label “Antoine Marchand”, distributed by Challenge Records.
Over the course of a forty-five-year career Ton Koopman has appeared in the most important concert halls and festivals of the five continents. As an organist he has performed on the most prestigious historical instruments of Europe, and as a harpsichord player and conductor of the Amsterdam Baroque Orchestra & Choir he has been a regular guest at venues which include the Concertgebouw in Amsterdam, the Théatre des Champs-Elysées in Paris, the Philharmonie in Munich, the Alte Oper in Frankfurt, the Lincoln Center and Carnegie Hall in New York and leading concert halls in Vienna, London, Berlin, Brussels, Madrid, Rome, Salzburg, Tokyo and Osaka.
Between 1994 and 2004 Ton Koopman has been engaged in a unique project, conducting and recording all the existing Cantatas by Johann Sebastian Bach, a massive undertaking for which he has been awarded the Deutsche Schallplattenpreis "Echo Klassik", the BBC Award 2008, the Prix Hector Berlioz, has been nominated for the Grammy Award (USA) and the Gramophone Award (UK). In 2000 Ton Koopman has received an Honorary Degree from the Utrecht University for his academic work on the Bach Cantatas and Passions and has been awarded both the prestigious Silver Phonograph Prize and the VSCD Classical Music Award. In 2006 he has received the « Bach-Medaille » from the City of Leipzig. Recently Ton Koopman has embarked on another main project: the recording of the whole works by Dietrich Buxtehude, one of the great inspirer of the young J.S. Bach. The recording will be accomplished in 2010 with the release of 30 CDs. Ton Koopman is President of the “International Dieterich Buxtehude Society”. Ton Koopman is very active as a guest conductor and he has collaborated with many prominent orchestras in Europe, USA and Japan. He has been Principal Conductor of the Netherland Radio Chamber Orchestra and has collaborated with the Royal Concertgebouw Amsterdam, DSO Berlin, Tonhalle Orchestra Zurich, Orchester des Bayerischen Rundfunks in Munich, Boston Symphony, Chicago Symphony, Orchestre Philharmonique de Radio France, Cleveland Orchestra, Santa Cecilia in Rome, Deutsche Kammerphilharmonie and Wiener Symphoniker. In the following season he will work on new programmes with the New York Philharmonic, DSO Berlin, Orchestra RAI in Turin, Stockholm Philharmonic, Tonhalle in Zurich. After the great success of his tour at the beginning of 2008, Ton Koopman has been nominated Artist in Residence at the Cleveland Orchestra for three consecutive years starting in 2011. Ton Koopman publishes regularly and for a number of years he has been engaged in editing the complete Händel Organ Concertos for Breitkopf & Härtel. Recently he has published Händel’s Messiah and Buxtehude‘s Das Jüngeste Gericht for Carus. Ton Koopman leads the class of harpsichord at the Royal Conservatory in The Hague, is Professor at the University of Leiden and is a Honorary Member of the Royal Academy of Music in London. Ton Koopman is artistic director of the French Festival “Itinéraire Baroque”.