The Breton regionalist union (Union Régionaliste Bretonne or URB) was a Breton cultural and political organisation created August 16, 1898. It was a broadly conservative grouping dedicated to preserving Breton cultural identity and regional independence. It expressed the ideology of mainly middle-class and aristocractic groups to secure continuity in local administration and Breton culture.
The Union was created in August 1898, in Morlaix, following festivals devoted to Breton culture. It was chaired by Anatole Le Braz, with the Marquis de Estourbeillon. François Vallée was named president of the section dedicated to Breton language and literature, with François Jaffrenou as secretary. Other important figures were the writers Alphonse de Chateaubriant, Louis Tiercelin and Charles Le Goffic. The photographer and publisher Émile Hamonic was also a member.
Sympathisers, if not supporters, included the politician Albert de Mun, the poet and art critic Jean Le Fustec, the linguist and grammarian François Vallée, the composer Louis Bourgault-Ducoudray, the singer Théodore Botrel, the scholar Rene de Kerviler, the composer Guy Ropartz and many others.
The prominent position held by the nobility and the clergy quickly alienated some of the more radical members and led to the foundation of the alternative Association des bleus de Bretagne (Blues of Brittany) in 1899, which had a more liberal-progressive agenda. Nevertheless, the two groups were never in open conflict. Le Braz was a member of both.