He dealt combatively with a most perplexing problem which had evolved out of the Church’s sense, perceptible already in the writings of Paul, that the one God is experienced in three aspects, as Father, Son and Spirit – creator, redeemer and strengthener. But what was the relationship between them? Oneness in divinity was somehow reflected in threeness – indeed, one would need a word to express that idea of threeness. It is to be found for the first time in Tertullian’s writings, although probably he did not invent it: Trinitas.
