The Gueydon was an armoured cruiser of the French Navy, lead ship of her class. She was named in honour of Louis Henri de Gueydon, first governor of Algeria under the 3rd Republic. Gueydon was commissioned in Toulon harbour in 1903, and undertook a first campaign to East Asia. She took part in the First World War, supervising patrols in Southern America and in the Caribbean. In 1923, she was refitted in Brest harbour. In 1926, she was again modified to serve as a gunnery school; she entered this role the following year, replacing the armoured cruiser Pothuau in Brest.