The founder, having heard that it was probable that Pope Gregory X, then holding a council at Lyon, would suppress all such new orders as had been founded since the Lateran Council, having commanded that such institutions should not be further multiplied, went to Lyon.
Petrus Zwicker (died 1403 in Vienna) was an East Prussian Inquisitor and cleric of the Roman Catholic Order of the Celestines.
He was largely engaged in mural paintings for churches, and specimens of his art will be found in the Abbey of St. Denis, in St. Paul at Nîmes, St. Polycarp at Lyons, the Oratory at Birmingham, the Church of the Celestines at Avignon, and in Strassburg Cathedral.