why was miguel de unamuno in house arrest before his death?

Answer 1

At a large rally held at the University of Salamanca in October 1936 Unamuno, Rector of the University, gave an extremely stirring reply to Grl. Millan Astray's (leader of the Foreign Legion) shouts of "Abajo la inteligencia" and "Viva la muerte". Unamuno was too prominent internationally to shoot or imprison, so he was confined to house arrest, where he died within a few months.

Answer 2

This was the second time this happened. He was against the policies of Generalissimo Franco.