Jeunesse ouvrière chrétienne
Congar was an early advocate of the ecumenical movement, encouraging openness to ideas stemming from the Eastern Orthodox Church and Protestant Christianity. He promoted the concept of a "collegial" papacy and criticised the Roman Curia, ultramontanism, and the clerical pomp that he observed at the Vatican. He also promoted the role of lay people in the church. Congar worked closely with the founder of the Young Christian Workers, Joseph Cardijn, for decades.