Codebreaker and computer pioneer Alan Turing was also responsible for the first recording of computer music. He hadn’t been intending to create a musical machine when he programmed computer-generated notes; they were meant as signals to the user of a complete job or the more troubling “digits overflowing in memory.” Yet the innovation resulted in three tunes that survive on a 12-inch acetate disc from 1951.

Jack Copeland, a professor in arts at the University of Canterbury (and author of a Turing biography), and composer Jason Long recently restored this experimental recording. The New Zealand–based researchers shared their process and findings in a post last month on the British Library blog. In it, they note that “computer-generated notes were emerging from a loudspeaker in Turing’s computing lab as early as the autumn of 1948,” which is well ahead of other innovators in computer music. The BBC unit that originally recorded the three songs — “God Save the Queen,” “Baa Baa Black Sheep,” and Glenn Miller’s “In the Mood” — had some distortion on its acetate disc, so a big challenge for the pair was discovering the pitch that would best reflect the sound of Turing’s Mark II computer.

They describe how Turing adapted the huge machine at the Computing Machine Laboratory in Manchester to play specific notes:

The Manchester computer had a special instruction that caused the loudspeaker—Turing called it the ‘hooter’—to emit a short pulse of sound, lasting a tiny fraction of a second. Turing said this sounded like ‘something between a tap, a click, and a thump’. Executing the instruction over and over again resulted in this ‘click’ being produced repeatedly, on every fourth tick of the computer’s internal clock: tick tick tick click, tick tick tick click. Repeating the instruction enough times like this caused the human ear to hear not discrete clicks but a steady note, in fact the note C6, two octaves above middle C.

He then found that different patterns of “hoots” created different notes. Teacher Christopher Strachey, who became curious after reading Turing’s Programmers’ Handbook for Manchester Electronic Computer Mark II, came by the lab with an idea for playing a series of notes in a long program. After a night spent with the machine, Strachey got it to perform “God Save the Queen” by morning.

The recording has a few glitches — the BBC noted that you can hear an an engineer quip that the computer is “not in the mood” for Glenn Miller. But it’s pretty amazing to hear this archive of sound from Turing’s lifetime. It’s also worth pointing out, whenever his impact is highlighted, that we might have had more of Turing’s contributions if the British government hadn’t persecuted him for being gay.

Turing committed suicide in 1954 after being convicted of “gross indecency” with another man in 1952, barely a year after this recording was made. As part of his probation, he was chemically castrated. Only in 2013 did he receive a posthumous royal pardon. Today, around 49,000 men who were similarly convicted before the 1967 decriminalization of homosexuality in the UK remain without such pardons. As the Independent reported last month, Prime Minister Theresa May’s government has “committed to” an “Alan Turing law” that would pardon those men, although it is still pending.

“It was a beautiful moment when we first heard the true sound of Turing’s computer,” Copeland and Long write in their blog post. Now you can, too, and be reminded once again of his visionary legacy.

Read more about the restoration of the first recording of computer music online at the British Library.