Johann Sebastian Bach
Johann Sebastian Bach was German composer, harpsichordist, organist, violist, violinist of the Baroque period. He is considered to had brought baroque music to it's ultimate maturity. When reading that many of his numerous Fugues were not actually a work of many weeks spent with composing but rather an improvisation on a given theme, I stand in awe. They're really complex and freaking hard to learn to play. Most of you have probably heard Toccata and Fuge in D Minor, BWV 565 (it was e.g. used as a opening theme for one of the french animated series about humans and their history, I believe the "Once Upon a Time... Man" one but I'm not 100 % sure), but that's not the piece I'm going to talk about today, even though it's also for organ ;-)
Another few notable pieces that pop to my mind for other instruments are the Brandenburg Concertos for Chamber ensembles (usually string ones, but there's also flutes used in some of the concertos, for example) or the Well-Tempered Clavier for solo keyboard (in baroque usually harpsichord, today usually piano) or the unfinished The Art of Fugue, considered by some music historians as pure intellectual practise.
While Bach's compositions are of great intellectual depth, technical difficulty and artistic beauty, in his days he was conversely considered not one of the best composers, but rather one of the best organists. But indeed, he certainly was a great virtuoso, especially on the organ, but also on harpsichord (which he was among the first in the world to use as a solo instrument) and violin. The number of musical pieces he wrote is huge — just a list of them takes up more than 16 A4 pages… He died in 1750 at the age of 65.
Passacaglia and Fugue in C minor, BWV 582
It's a work for organ and while presumably composed early in Bach's life it's definitely one of his best works. Robert Schumann described the variations of the passacaglia as "intertwined so ingeniously that one can never cease to be amazed."
The first part of this work is, as the name suggests, a passacaglia. The passacaglia is a musical form with origins in Spain in 17th century that is usually of serious character and which is usually series of continuous variations around a ground bass theme. The term passacaglia itself, in Spanish pasacalle, is derived from Spanish pasar (to walk) and calle (street). Quite a fitting name, I'd say. You'll probably get the meaning easily after hearing it once — listen to the initial bass theme which is then repeated over and over throughout the whole piece. Passacaglia is similar in form to chaconne (Bach also wrote an awesome one, for violin as part or Parita No. II D minor, BWV 1004, later adapted by various composers for other instruments as well).
This particular passacaglia has a total number of 20 variations. Most scholars agree that the structure is such: first the passacaglia builds up to its climax in twelve variations, this is followed by an intermezzo formed by three quiet variations to finally end up the passacaglia with another 5 variations.
It then, without any break, flows into it's second part — fugue, in this case double fugue. Fugue is a contrapuntal composition (formed by two or more musical lines that sound very different and move independently from each other but sound harmonious when played simultaneously) in two or more voice built upon a theme that is introduced at the beginning and recurs frequently during the course of the composition. It is usually divided into three parts: exposition (opening of the fugue, the theme is introduced and all voices has entered), development and recapitulation (contains the return to the main theme in the fugue's opening key). That it's double fugue means there are actually two themes that the fugue is developed on. In this piece, the first half of the bass theme from passacaglia is used as the first theme for the fugue, while the second half is used as the second theme for the fugue. Witty, isn't it ;-)
As Bach has been dead for some time now, the copyright on his works already expired and they are in public domain. You can download the musical score (legally and for free) for this piece at International Music Score Library Project.
Ton Koopman
Ton Koopman is a conductor, organist and harpsichordist born in 1944 in Netherlands. He studied organ, harpsichord and musicology in Amsterdam and specialized in Baroque music. Throughout his career he had concentrated on Baroque music and especially Bach. He recorded complete set of Bach cantatas and organ works and is now concentrating on works composed by Dieterich Buxtehude, who was a great influence to Bach. He plays on historical instruments and aims for authenticity. Some of his organ interpretations have however drawn criticism for their overuse of ornamentation.
Personally, I deem him to be one of the best organists but I tend to like slower tempos than he uses for many of the pieces I have heard him play, on the other side, his articulation is very clear and he seems to be able to nicely draw out all the voices present in a composition.
And of course, not to forgot, here're links (actually on youtube it's saved as two videos):
Ton Koopman — J. S. Bach: Passacaglia and Fugue in C minor, BWV 582, Part I. Passacaglia and
Ton Koopman — J. S. Bach: Passacaglia and Fugue in C minor, BWV 582, Part II. Fugue