Metropolite Piotr Mohyła (1596-1647) was the author of the Uniate Memorial, a tract proposing the restoration of unity between Orthodoxy and Roman Catholicism, which was published anonymously in 1645.The dogmatic foundation of the whole project is the affirmation of one faith, which unites the divided churches. It opens to each in the same measure participation in the mystery of salvation. The stress laid on the soteriological identity of faith held by both churches seems to be the decisive factor in Mohyla’s readiness to meet Catholic dogmas halfway. Mohyła is prepared to debate, come to an agreement and compromise on such thorny issues as the Catholic interpretation of filioque, papal primacy, or the purgatory. One of the consequences of adopting a common soteriology would be a clear guarantee of a separate theological identity to members of the Orthodox church united with Rome.In his tract Mohyła rejects the soteriological exclusivism of the Catholics, which was upheld in the formula of papal primacy and the articles of the Union of Brześć. He suggests instead the definition of papal primacy adopted at the Council of Florence. Mohyła rejects as well the papal claim to demarkate the borders of the visible church and the sphere of the salvatory efficacy of mercy. The Act of Union concluded in Brześć in 1596 is in his opinion the opposite of a genuine reconciliation because its authors ignored the true dogmatic principles which would grant Orthodoxy a soteriological equality with Catholicism.The third aspect of Mohyla’s discussion of soteriology is his insistence on the validity the sacrament of baptism conferred by Constantinople. He stresses the common legacy of saving faith, which was brought to Kiev from Constantinople in 988. By pointing to baptism as the most important common link between the Catholic and the Orthodox Churches, Mohyta develops his idea of union, which assumes a reconciliation between Rome and Constantinople. He argues that the acknowledgment of the efficacy of baptism received from Byzantine capital implies a symmetrical model of the relations of the Kiev Metropoly with both Rome and Constantinople. Baptism is a precious reminder of the ancient unity of the Church in the East and in the West. By giving full weight to the memory of the Baptism of Kievan Rus in 988, the Memorandum of 1645 reminds its readers of the universal character of salvation and paves the way to the reunion of the Catholic and the Orthodox Church.