Julien Cosmao
| Julien Cosmao | |
|---|---|
| Portrait of Julien Cosmao by Auguste Mayer | |
| Native name | Julien Marie Cosmao-Kerjulien | 
| Nickname(s) | « Va de bon cœur » | 
| Born | 27 November 1761 Châteaulin, Finistère | 
| Died | 17 February 1825 Brest, France | 
| Buried | St Martin Cemetery, Brest | 
| Allegiance | Kingdom of France Kingdom of the French French First Republic First French Empire | 
| Service | French Navy | 
| Years of service | 1776 – 1816 | 
| Rank | Counter admiral | 
| Commands | Le Tonnant, Le Pluton | 
Julien Marie Cosmao-Kerjulien (27 November 1761 – 17 February 1825) was a French Navy officer best known for his actions during the Battle of Trafalgar.