Johann Sebastian Bach, born March 31, 1685 - July 28, 1750, was a German composer and musician of the Baroque period. He is known for instrumental compositions such as the Brandenburg Concertos and the Goldberg Variations as well as for vocal music such as the St Matthew Passion and the Mass in B minor. Since the 19th-century Bach Revival, he has been generally regarded as one of the greatest composers of all time. To a large extent, Bach's musical style fits in the conventions of his day, which is the final stage of the baroque style. Religious music was at the center of Bach's output for much of his life. The hundreds of sacred works he created are usually seen as manifesting not just his craft but a truly devout relationship with God. He had taught Luther's Small Catechism as the Thomaskantor in Leipzig, and some of his pieces represent it The Lutheran chorale was the basis of much of his work. In elaborating these hymns into his chorale preludes, he wrote more cogent and tightly integrated works than most, even when they were massive and lengthy. The large-scale structure of every major Bach sacred vocal work is evidence of subtle, elaborate planning to create a religiously and musically powerful expression. For example, the St Matthew Passion, like other works of its kind, illustrated the Passion with Bible text reflected in recitatives, arias, choruses, and chorales, but in crafting this work, Bach created an overall experience that has been found over the centuries since to be both musically thrilling and spiritually profound. Bach published or carefully compiled in manuscripts many collections of pieces that explored the range of artistic and technical possibilities inherent in almost every genre of his time except opera. For example, The Well-Tempered Clavier comprises two books, each of which presents a prelude and fugue in every major and minor key, displaying a dizzying variety of structural, contrapuntal, and fugal techniques.