38 And We, Venerable Brethren, as We celebrate the fifteenth centenary of this heavenly birthday, have no more earnest desire than to see all who can be called Christians take St. Cyril as their model, and work ever more and more zealously for the happy return of our separated brethren in the East to Us and to the one Church of Jesus Christ. Let there be in all one faith inviolate; in all one charity, uniting all together in the mystical Body of Jesus Christ; in all one earnest and practical loyalty to the See of Blessed Peter.
Source: Orientalis Ecclesiae (Vatican.va)