Saturday is J.S. Bach’s birthday, by most accounts. He was born on March 21, 1685, in Eisenach, one of the Germanic hamlets in Thuringia. The debate about whether his birth date was under the Julian or Gregorian calendars is best left to academics.

Most of the world accepts Saturday as Bach’s birthday, and I think we should go with the majority. So Happy Birthday, Johann Sebastian! A young 324 years old!

Incidentally, 1685 was a banner year for great composers. Bach, Handel, Domenico Scarlatti -- all were born in 1685.

But it’s Bach we’re celebrating on Saturday and a great way to do it -- and without cost, to boot -- is being sponsored by the Twin Cities chapter of the American Guild of Organists.

Starting at 9 a.m. you can attend free concerts at a variety of venues near Summit Avenue in St. Paul. Each concert lasts about an hour. Call it a concert crawl. Here’s the schedule:

9 a.m. St. Mary Chapel of the Saint Paul Seminary, 2260 Summit Ave.: The program features organist David Jenkins, members of the Minnesota Chamber Ensemble and a choir of members of the National Lutheran Choir and Bach Society.

10:30 a.m. St. Thomas Aquinas Chapel, University of St. Thomas, Cleveland and Ashland avenues: All-organ recital by James Callahan and Timothy Buendorf.

1 p.m. St. John the Evangelist Episcopal Church, 60 Kent St.: Organ recital featuring Sharon Kleckner and James Frazier. Bach dominates, though there’s also a selection by Franz Liszt.

2:30 p.m. Unity Unitarian Church, 732 Holly Ave.: Performers include organist Kraig Windschitl, pianist Richard Tostenson and tenor Aaron Humble. You’ll also hear a work by George Rochberg titled “Nach Bach.”

4 p.m. House of Hope Presbyterian Church, 797 Summit Ave.: Organ recital by Aaron David Miller and Charles Echols. More Bach, plus a work by Porter Heaps titled “Swinging Bach.”

7 p.m. Saturday night’s big Bach event is a performance of “The Passion According to St. Matthew” by the National Lutheran Choir at St. Olaf Catholic Church, 215 S. 8th St., in downtown Minneapolis. It’s a ticketed event, $25-$35. Go here for ticket information.

Still not enough? Rent the off-beat 1968 film by Jean-Marie Straub and Daniele Huillet, “The Chronicle of Anna Magdalena Bach,” though you’ll have to go online to do it. Deliberately stilted, the film features keyboardist/conductor Gustav Leonhardt in a funny wig as Bach and Christiane Lang as Bach’s second wife -- though mostly you only hear her fictional over-narrative as excerpts of music are shown being performed in chronological order in authentic locales.

Or pick up a copy of James R. Gaines’ wonderfully intriguing book, “Evening in the Palace of Reason,” which describes the meeting between J.S. Bach and Frederick the Great and the inspiration for the great “Musical Offering.”

Happy Baching. If you know of any other contrapuntal birthday events, even if you're hosting something in your own Bachyard, send a comment.