In his Holy Sonnets, Donne seeks to forget rather than remember his sins, begging God for ‘a heavenly Lethean flood’ to ‘drown’ his ‘sin’s black memory’ and implying that his very salvation may depend upon it: ‘That Thou remember them, some claim as debt; / I think it mercy if Thou wilt forget’. Such a desire for divine oblivion would seem to be the very inverse of the theologian Dr Donne’s well-known assertion that ‘the art of salvation is but the art of memory’, yet, this chapter argues, they are intimately joined in the Holy Sonnets. This chapter explores how the speaker’s uncertainty about his salvation connects the ‘art of death’ (ars moriendi) with the ‘art of memory’ (ars memorativa) as a mnemonic poetics of ruin and recollection. The transformation of the art of memory into an art of salvation in Augustine’s Confessions is central not only to Donne’s reputation as a ‘second St Augustine’ but also to the poetics of memory that shape the Holy Sonnets. Donne constructs the Holy Sonnets as a memory theatre in which to enact the drama of salvation by performing the role of Doctor Faustus, a part drawn from both Augustine’s Confessions and Marlowe’s Doctor Faustus.