How an A note became an A note

TL;DR

The musical standard of A440 Hz emerged through centuries of argument, national politics, and a 1939 BBC conference, not natural law.

Key Points

• 1.Early pitch had no standard and varied wildly. Before tuning forks, musicians tuned to the hardest-to-tune instrument, usually the organ; a city in northern France in 1700 played A at 374 Hz while southern France played it at 563 Hz.
• 2.Post-revolutionary France drove the first serious standardization push. Inspired by the metric system, France convened a government commission and set A at 435 Hz in the mid-1800s, spreading it across Europe and the US as the dominant standard.
• 3.Rising pitch created cultural anxiety over preserving classical music. As pitch crept upward, musicians feared iconic pieces like Mozart's 'Queen of the Night' aria from The Magic Flute would become unsingable, driving urgency to lock in a lower standard.
• 4.American percussion maker John Degan championed A440 for partly commercial reasons. Degan convinced the American Federation of Musicians and major music associations to adopt 440 Hz — a standard conveniently matching instruments he manufactured, potentially locking out European competitors.
• 5.A 1939 BBC-led conference unified Europe and the US on A440 on the eve of WWII. Representatives from Germany, England, France, Italy, and the Netherlands gathered in London just months before the war, with the BBC framing shared musical standards as a tool for fostering peace.
• 6.Conspiracy theories falsely blame A440 on Nazis or the Rothschilds. Online theories claim 440 Hz was designed to harm listeners or manipulate bodies; historian Fanny Grabenhorst found no evidence of malicious intent — it was the British who led the charge, adopting what the American music industry had already decided.
• 7.Music historian Fanny argues pitch standardization is ultimately fluid. She concludes the A note matters less as a universal law and more as a local agreement among musicians in a room, since pitch naturally fluctuates with temperature and tuning drift during any performance.