Ravel had a lifelong friendship with various members of the Gaudin family whose home was in Saint-Jean-de Luz. In particular Marie Gaudin and her sister Jane Courteault were among his regular correspondents throughout his life.
The Ravel and Gaudin families seem originally to have become acquainted through Ravel's great-aunt Engrâce Billac (also called Gracieuse or Gachoucha) who was in service as maid and governess to the Bibal family in Saint-Jean-de-Luz; after the marriage in 1875 of Annette Bibal and Edmond Gaudin (who had a fish preserving business), Gachoucha remained with the Gaudin couple, and brought up most of their seven children. These included:
Charles (1875-1910) was a sea captain who died in an accident in the Congo in 1910. On that occasion Ravel wrote a heartfelt letter of condolence to his widow Magdeleine Gaudin-Hiriart (reproduced in Rousseau-Plotto  p.69). Their son Edmond became close to Ravel in his later life. Edmond owned a car and used to drive Ravel to places in the Basque country; in 1932 they went to San Sebastian to see the bullfighting.
Pierre (1878-1914) succeeded his father as head of the fish preserving business. See below.
Marie (Marie-Bernardine) (1879-1976) remained unmarried and lived in Saint-Jean-de-Luz at 41 rue Gambetta, where Ravel several times stayed during the 1920s, and she was the recipient of many letters in which he shared his private feelings and anxieties. She was one of the first to observe the onset of the illness which affected his physical coordination: in 1932 when they were playing at skimming stones across water, Ravel accidentally threw one into her face. Marie Gaudin lived to see the 1975 centenary of Ravel's birth, and in that year at the age of 96 she was interviewed for a Belgian TV film to recall her memories of the composer.
Jeanne (1880-1979) married Henri Courteault, director of the Archives Nationales, and she lived largely in Paris where she was frequently in touch with Ravel, especially in his last years. She and her sister Marie both attended Ravel's funeral.
Pascal (1883-1914) also worked in the fish trading business.
The brothers Pierre and Pascal Gaudin both died during the First World War. On the outbreak of war, they immediately joined the army, and both were enrolled in the 49th infantry regiment. Both of them were killed by the same shell on the first day of their arrival at the front, 12 November 1914, at Oulches. Ravel commemorated them by dedicating to them the Rigaudon in Le tombeau de Couperin. Étienne Rousseau-Plotto has remarked on the verbal echo between "Gaudin" and "Rigaudon"; and his book Ravel, portraits basques is the source of many interesting details about the relationship between the Ravel and Gaudin families.