Centennial of the Letter of Pope Saint Pius X on the promulgation of the Catechism of Christian Doctrine:

LETTER FROM THE HOLY FATHER PIUS X

TO CARDINAL PIETRO RESPIGHI

VICAR OF ROME

BY WHICH THE APPROVAL

OF THE CATECHISM OF CHRISTIAN DOCTRINE

IS GIVEN FOR THE DIOCESES AND ECCLESIASTICAL PROVINCE

OF ROME 

 
 (Rorate Caeli;here)