The archbishops and secular clergy found active co-workers among the regular clergy (i.e. religious orders). Among the orders represented in Sweden were the Benedictines, Cistercians, Dominicans, Franciscans, Brigittines (with the mother-house at Wadstena) and Carthusians. A Swedish Protestant investigator, Carl Silfverstolpe, wrote: "The monks were almost the sole bond of union in the Middle Ages between the civilization of the north and that of southern Europe, and it can be claimed that the active relations between our monasteries and those in southern lands were the arteries through which the higher civilization reached our country."