For someone who never wrote a major treatise on the subject, Karl Rahner exercised a remarkable influence on the field of trinitarian theology. His main production was a chapter of eighty-five pages written in 1967 and titled “Der dreifaltige Gott als transzendenter Urgrund der Heilsgeschichte” (”The Threefold God as Transcendental Ground of Salvation History”)f or the second volume, Die Heilsgeschichte vor Christus (Salvation History Before Christ), of Mysterium Salutis: Grundriss heilsgeschichtlicher Dogmatik (Mystery of Salvation: Outline of a Dogmatic Theology Based on Salvation History). Two years later he wrote two substantial articles, “Trinität” and “Trinitätstheologie,” for the German original of the theological encyclopedia Sacramentum Mundi, the first being closely modelled on “Der dreifaltige Gott.” This (”Der dreifaltige Gott”) was published in English translation as a separate work (a book) titled The Trinity in 1970; and the English versions of the above-mentioned articles, “Trinity, Divine” and “Trinity in Theology,” appeared in volume vi of the English Sacramentum Mundi in 1970. In this chapter, the references will generally be supplied in the text so as to avoid overloading the footnotes. The majority of the references will be to The Trinity, whose title will be abbreviated to Trin. Of the two articles, only the first will be quoted. Finally, apart from the conclusion, the sections of this chapter will correspond in content and relative length to those of The Trinity.