In modern Orthodoxy, the `Greek' practice, based on Cyprian, of receiving converts by (re -)baptism contrasts with the `Russian' approach, consistent with Augustine, of requiring mere profession of faith and/or chrismation. Is one approach more deeply rooted in Orthodox tradition? Against a modern tendency to champion Cyprian's narrower ecclesiology, the twentieth-century Russian émigré theologian Georges Florovsky argued forcefully that the distinction found in Augustine's De Baptismo between sacramental `validity' and `efficacy' can and should be the basis for contemporary articulations of Orthodox sacramental theology. Beyond the juridical plane, Florovsky considered Augustine's indispensable contribution to be an understanding of schism as what Florovsky calls a `dissipation of love'. It is through a creative appropriation of this insight—presenting its flip -side, as it were — that Florovsky is able to recognise `preparatory grace', already at work as a will and a thirst for unity, in presently separated communities. Significant insights of eucharistic ecclesiology corroborate the compatibility between Augustinian and Orthodox ecclesiology, and show how a full recognition of non- Orthodox baptisms neither obscures the reality of division nor minimises the imperative to overcome it.