It is said that in medieval times Catholic and Orthodox Christians excommunicated each other. Do you recognise each other’s baptisms or do you each believe the faith of the other to be erroneous?
The great schism between East and West is generally dated to have taken place in 1054, when the Latin Cardinal Humbert da Silva Candida (on 16 July 1054) excommunicated the Patriarch of Constantinople, Michale Kerullarios, and his companions; on 24 July 1054 he, in turn, declared the Roman legates and their staff an anathema. This excommunication was, however, restricted to individual people. After 1054 there were still numerous examples for practised Church unity between Orthodox and Catholics and numerous attempts at reconciliation (e.g. Union Council of Lyon 1274, Union Council of Ferrara-Florence 1438/39), which, however, failed for various reasons. Only in the 18th century the communion finally split. The decree of the Roman Congregation of the Propagation of the Faith (Propaganda fide) of 1729 prohibited any sacramental communion between Catholics and Orthodox; conversely, an encyclica of the Greek patriarchs of 1755 declared Latin Christians as unbaptised.
On 7.12. 1965 Rome and Istanbul both lifted the anathema of 1054 from the memory and from the midst of the Church.
As regards the recognition of baptism, Catholics recognise baptism in an Orthodox Church, while the various Orthodox churches vary in their approach (some recognise Roman-Catholic baptism, others, such as the Church of Greece, do not). Further reading: J. Oeldemann, “Orthodoxe Kirchen im ökumenischen Dialog. Positionen, Probleme, Perspektiven” (Paderborn 2004) (This reply was written by Prof. Dr. M. Th. Hainthaler, Phil.-Theol. Hochschule Sankt Georgen, Frankfurt am Main )