In August 1898, in Morlaix the Breton Regionalist Union was founded by Régis de l'Estourbeillon under the chairmanship of Anatole le Braz.
He became acquainted with the printer Alexandre Le Goaziou and with him created Ar Vro (The Nation) whose first issue appeared on 1 March 1904.
He continued to be active in the Breton Regionalist Federation, and participated in the journal La Bretagne libertaire in 1923.
He also wrote numerous articles, plays and books, including Buhez Sant Erwan, An Hirvoudou (1899), An Delen Dir (1900), Breiziz (1911).
These topics were the subject of a long controversy and numerous articles published in his journal An Oaled in which Jaffennou set himself against the BNP, which retaliated by attacking his regionalist ideology and his links to the French political elitr.
This report contains as its main feature the cutting of Brittany into three parts: The Ille-et-Vilaine is attached to the English Channel to form an economic region.
Already, we take a stand against Taldir-Jaffrennou's monstrous project, which singularly corroborates all the evidence that we have from Vichy.He signed an agreement with Marshal Philippe Pétain in December 1940 and participated in the Breton Advisory Committee (1942), seeking to promote Breton political, economic and cultural rights in the difficult war years.
At this point, Jaffrennou abandoned his previous moderate regionalist position, which he declared "obsolete and outdated", and now advocated complete independence for Brittany.
Rejecting his earlier decision to cease publishing during the war, he now wrote for L'Heure Bretonne and completely broke with his past views.
On 7 August 1944, Jaffrennou was arrested by members of the French resistance on charges of having served the enemy and supported Pétain.
However, M. Baudet-Germain, a Vichy official, (Secretary General of the Prefecture Regional Rennes), said he had received a letter from Jaffrennou denouncing the Resistance leader Adolphe Le Goaziou.
However the testimony was sufficient to convict Jaffrennou to 5 years imprisonment, confiscation of a quarter of his property and national indignity.
Le Goaziou, who had been made President of the Finistère Departmental Liberation Committee, said he has always maintained a good relationship with Jaffrennou, never doubted his sincerity, and shared his regionalist political beliefs, but he regretted that he had sullied his reputation by dealing with Vichy.
It is also believed that the famous Austrian Jewish writer Leo Perutz, a member of the Gorsedd of Brittany, wrote two letters, one addressed to the Attorney General of the Court of Appeal of Rennes on 16 July 1945, (No.
As a result of international interventions in particular from Great Britain and Israel, Jaffrennou was pardoned, initially in 1945 and then definitively in 1946 by Georges Bidault, President of the Council of Ministers.