How did Josephine come to be “Josephine”?

Regarding the name Josephine
Letter to the Bulletin, published by the Napoleonic Society of America.

In Bulletin 50 a reader asked whether it was Napoleon who changed Rose’s name to Josephine. Although little is known about how or why Rose changed her name to Josephine, most historians seem to agree that it was Napoleon who instigated it. For one thing, he addresses her by the name Josephine in his letters to her. However, in Napoleon’s Viceroy, Carola Oman claims that Josephine signed a letter Josephine de Beauharnais as early as 1792, several years before she met Napoleon.1 One would have to see the original letter to know for sure, but it seems unlikely: if Rose were using the name Josephine as early as 1792, surely it would have appeared on other correspondence as well.

The following paragraph in the introduction to Impératrice Josephine; Correspondance, 1782-1814, clearly outlines all the changes Rose/Josephine went through:

“It is likely that until October, 1779 Josephine used her first name Rose, or more familiarly, Yeyette. After her marriage to Alexandre de Beauharnais, she signed herself Vicomtesse de Beauharnais or even Lapagerie de Beauharnais. In 1790, she became Citoyenne Beauharnais, sometimes followed by the words, wife of a maréchal de camp. Alexandre’s execution stood out by the appearance of widow Beauharnais or Lapagerie-widow Beauharnais which she put at the bottom of letters after July, 1794. On March 9, 1796, she initialed M.R.J. Tascher to the certificate of marriage to Napoleon. Becoming Madame Bonaparte, she henceforth made use of her two names, Lapagerie-Bonaparte or Tascher-Bonaparte (she sometimes used the Italian spelling Buonaparte). At the start of the Consulate, she adopted Josephine Bonaparte, which the proclamation of Empire in May, 1804 reduced to the first name Josephine alone, by which she was enthroned Empress of the French and entered into posterity.”2

Footnotes:

1. Oman, Carola, Napoleon’s Viceroy; Eugène de Beauharnais (New York: Funk and Wagnalls, 1966), p. 34.
2. Impératrice Josephine; Correspondance, 1782-1814, Chevallier, Catinat and Pincemaille, editors (Paris: Histoire Payot, 1996), p. III. The translation from the French is my own.