Caption: Le Serment du Jeu de paume, 1791.

The Tennis Court Oath (1789 Jun20) was one of most notable events of the early days of the French Revolution.

The delegates to Estates-General of 1789 swore, loosely speaking, to continue the reform of France---but they forgot about angular measurment, and so the metric system didn't include angular units.

Vive la France: Casablanca (1942 film): La Marseillaise | 1:55 or Civilisation 12 (1969 documentary): La Marseillaise | 1:44.

Credit/Permission: Jacques-Louis David (1748--1825), 1791 (uploaded to Wikipedia by User:Tablar, 2006) / Public domain.
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