Jan Pieterszoon Sweelinck (1562 – 1621) was a Dutch composer, organist, and pedagogue whose work straddled the end of the Renaissance and beginning of the Baroque eras.
He was among the first major keyboard composers of Europe, and his work as a teacher helped establish the north German organ tradition.
According to Cornelis Plemp, a pupil and friend of Sweelinck's, he started his 44-year career as organist of the Oude Kerk (Amsterdam) in 1577, when he was 15. This date, however, is uncertain, because the church records from 1577 to 1580 are missing and Sweelinck can only be traced in Oude Kerk from 1580 onwards; he occupied the post for the rest of his life.
Sweelinck represents the highest development of the Dutch keyboard school, and indeed represented a pinnacle in keyboard contrapuntal complexity and refinement before J.S. Bach.
This is a small set of variations on the well-known hymn: Puer nobis nascitur (Een kind is ons geboren // Ein Kind ist uns geboren)