Capelle was called "the soul of the movement" when in 1956 the first International Conference for Living Latin () took place in Avignon,Goodwin B. Beach, "The Congress for Living Latin: Another View", The Classical Journal, Vol. 53, No. 3, December 1957, pp. 119–122: marking the beginning of a new era of the active use of Latin. About 200 participants from 22 different countries took part in that foundational conference.
