Chaitanya wrote almost nothing. Eight verses are attributed to him and no systematic work, and the theology of the tradition was produced by six scholars he sent to Vrindavan to recover the sites associated with Krishna and to put the teaching in order. Rupa and Sanatana Goswami were brothers who had held office under the sultan of Bengal; Jiva Goswami, their nephew, wrote the philosophical treatises; Gopala Bhatta, Raghunatha Das and Raghunatha Bhatta completed the six.
Their central innovation is the treatment of religious emotion through the categories of Sanskrit dramatic theory. Rupa Bhaktirasamritasindhu takes rasa, the tasted flavour of an emotion that an audience experiences, and applies it to devotion, sorting the relationships a devotee may have with Krishna into a graded set: the neutral, the servant, the friend, the parent and the lover, each more intimate than the last. The devotion is not preparation for knowledge but the goal itself, and its highest form is the love of the cowherd women of Vrindavan, and above theirs the love of Radha.
Jiva Goswami supplied the metaphysics under it, the doctrine that God and the soul are simultaneously one and different in a way the mind cannot reconcile. The inconceivability is doing real work: it is not an evasion of the contradiction but the claim that a relation between the infinite and the finite is not the kind of thing that resolves.