Nygren was one of the theologians who had formed the so-called Lundensian School of Theology, in which other important figures were Gustaf Aulén and Ragnar Bring.
He argues that from St. Augustine onward, the focus on agape became diluted by an attempt to synthesize the concept with that of eros, in a development centered on the Latin word caritas.
The Reformation, therefore, was hugely important because it inspired Martin Luther to expose the fallacy of the caritas synthesis, and made clear again the properly Christian conception of love, namely pure agape.
[2] For example, Martin Luther King Jr. shows clear influence by Nygren's categories in a sermon where he discussed Jesus' command to love one's enemies: When Jesus bids us to love our enemies, he is speaking neither of eros not philia, he is speaking of agape, understanding and creative, redemptive goodwill for all men.
"[3] A generation later, however, with the work of Paul Tillich and Karl Rahner, Christian theology has turned away from Nygren's stark dualism of agape and eros and back towards a more unified conception of love.
[4] For example, Pope Benedict XVI in his encyclical, Deus caritas est (2005), concluded that both eros and agape are aspects of divine love.