Catholic Answer The Church has always been concerned with Ecumenism, therestoration of unity among all Christians (see definitionbelow), since the first tragic split in the
…eleventh century whenthe Eastern part of the Church was torn from her by the privateambitions of men. Then, five centuries later, the protestant revoltresulted in whole nations being denied the sacraments. This unitywas bestowed by Christ on His Church from the beginning assomething she can never lose. However, the Church is tasked withthe preaching of the Gospel to her separated brethren in the hopesthat they return to the Church, even as we realize that we mustplace all our hope "in the prayer of Christ for the Church, in thelove of the Father for us, and in the power of the Holy Spirit."( Unitatis redintegratio 24 section 2). Please seeparagraphs 816, 820-822 in the Catechism and the Decree onEcumenism at the link below. From the Glossary in the Catechism of the Catholic Church: .
Ecumenism : Promotion of therestoration of unity among all Christians, the unity which is agift of Christ and to which the Church is called by the HolySpirit. For the Catholic Church, the Decree on Ecumenism of theSecond Vatican Council provides a charter for ecumenical efforts.(816, 820-822. (MORE) 
