Hodie Christus Natus Est (Latin for Today Christ is Born) is a Gregorian chant sung at Christmas and exists in various versions by different composers.
Sweelinck (May 1562– October 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. Sweelinck represents the highest development of the Dutch keyboard school and represented a pinnacle in keyboard contrapuntal complexity and refinement before J.S. Bach.