 The traditional account of identity, derived from Boethius, holds that things may be either generically, specifically, or numerically the same or different. Abelard accepts this account but finds it not sufficiently fine-grained to deal with the Trinity. The core of his theory of identity, as presented in his Theologia christiana, consists in four additional modes of identity: (1) essential sameness and difference; (2) numerical sameness and difference, which Abelard ties closely to essential sameness and difference, allowing a more fine-grained distinction than Boethius could allow; (3) sameness and difference in definition; (4) sameness and difference in property (in proprietate). Roughly, Abelard’s account of essential and numerical sameness is intended to improve upon the identity-conditions for things in the world given by the traditional account; his account of sameness in definition is meant to supply identity-conditions for the features of things; and his account of sameness in property opens up the possibility of there being different identity-conditions for a single thing having several distinct features.