Listen to Christmas Carols Performed by Alan Turing’s Computer in 1951

Alan Turing is a truly heroic figure. Thanks to his Enigma Machine, World War II ended much sooner than it would have had England not been able to decipher German communication. And, as it turns out, Turing was also a pioneer in electronic music. These Alan Turing Christmas carols were broadcast in 1951 — and performed by his computer.

After World War II, Turing started work at the Victoria University of Manchester. In 1948, he set up the Computing Machine Laboratory to work on advancements in computing. One of the things Turing worked on was a theoretical computer chess program. The program stayed in the realm of impossibility for a few years, as no computer was yet powerful to run it.

However, in Feb. 1951, the Computing Machine Laboratory got a new Ferranti Mark 1, the very first commercially available general-purpose computer. The Ferranti was a truly impressive machine, though even it was too slow to run Turing’s chess program. (Later that year, Dr. Dietrich Prinz wrote a chess program for the Mark 1, but it wasn’t a full game — it could only do mate-in-two puzzles, and it took as long as 20 minutes to solve them, and that was without a number of rules like castling.)

RELATED | After Alan Turing, Thousands of British Gay and Bisexual Men Are Finally Pardoned

While the Mark 1 failed in chess, it did, however, have a “hoot” command, which caused it to make noise. That noise could be modified in pitch. And if you can modify pitch, you can make music — of a sort. As a promotional demo of the Mark I, Turing’s friend Christopher Strachey made the earliest known recording of computer-generated music — a medley of “Baa Baa Black Sheep,” “God Save the King” and “In the Mood.”

In 2016, this original recording was restored, and you can hear it below:

That wasn’t the only music the Mark 1 made. In 1951, the BBC’s holiday broadcast included two Christmas carols — “Jingle Bells” and “Good King Wenceslas.” Sadly, this original broadcast wasn’t recorded, but Jack Copeland and Jason Long from the British Library — the same folks who restored the above recording — re-created the performance by splicing together recordings.

Copeland and Long described their process as “musical Lego”:

The performances on Cooper’s disc contained between them a total of 152 individual computer-generated notes. By manually chopping up the audio, we created a palette of notes of various pitches and durations. These could then be rearranged to form new melodies. It was musical Lego: endless new structures could be produced from these basic building blocks. The process of recreating the carols was not always straightforward, however. Sometimes the notes we needed were missing from the palette, since they did not appear in the three reference pieces. Missing notes had to be manufactured, first by calculating the closest frequency that the Ferranti computer could generate — it wasn’t always able to hit a note exactly — and then shifting the frequency of one of the specimens in the palette to achieve a match (while trying, moreover, to keep the specimen’s spectral signature the same, so as to maintain a natural sound). Another problem was duration: sometimes a note needed to be shorter or longer than the specimen in the palette, so we either pared the specimen down, or pieced together copies of it by hand.

While the Mark I made the very first computer music to be recorded, it didn’t make the first in the world. That honor goes to Australia’s first digital computer, the CSIRAC, which could perform “Colonel Bogey.”

Listen to the Alan Turing Christmas carols below: