Hodie Christus Natus Est

Today and tomorrow will be very busy, so I’ll get this up today.

Hodie Christus natus est (Latin for "Today Christ [was] born") is a Gregorian chant sung at Christmas. It exists in various versions.[1]

The words are also the title of various sacred works:

a mass by Giovanni Pierluigi da Palestrina[2]

a motet by Giovanni Gabrieli

a motet by Francis Poulenc[3]

This version is performed by Voices of Ascension, from the work of:

Jan Pieterszoon Sweelinck … 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 indeed represented a pinnacle in keyboard contrapuntal complexity and refinement before J.S. Bach. However, he was a skilled composer for voices as well, and composed more than 250 vocal works (chansons, madrigals, motets and Psalms).

Some of Sweelinck's innovations were of profound musical importance, including the fugue—he was the first to write an organ fugue which began simply, with one subject, successively adding texture and complexity until a final climax and resolution, an idea which was perfected at the end of the Baroque era by Bach. It is also generally thought that many of Sweelinck's keyboard works were intended as studies for his pupils. He was also the first to use the pedal as a real fugal part. Stylistically Sweelinck's music also brings together the richness, complexity and spatial sense of Andrea and Giovanni Gabrieli, and the ornamentation and intimate forms of the English keyboard composers. In some of his works Sweelinck appears as a composer of the baroque style, with the exception of his chansons which mostly resemble the French Renaissance tradition. In formal development, especially in the use of countersubject, stretto, and organ point (pedal point), his music looks ahead to Bach (who was quite possibly familiar with Sweelinck’s music).

For an example of Sweelinck’s style of organ playing, Variations on "Mein Junges Leben Hat Ein End":