Rerum Ecclesiae §9

⁹ At this point, Venerable Brothers, We wish to touch upon in passing a matter which is worthy of your most serious thought. All are acquainted, no doubt, with the grave damage which was done to the propagation of the faith as a result of the late War. Missionaries recalled to their own countries fell in the terrible conflict. Other missionaries were compelled to leave the field of their activities with the result that missionary work suffered greatly thereby. These damages and losses to the missions have to be made good if we hope to bring them back to the state in which they were before the War and to insure their further progress.