The aim of this book is to devise a method for approaching the problem of presence in Hellenistic and Roman poetry. The problem of presence, as defined here, is the problem of the availability or accessibility to the reader of the fictional worlds disclosed by poetry. From Callimachus' Hymns to the Odes of Horace, poets of this era repeatedly challenge readers by beckoning them to explore fictive spaces which are at once familiar and otherworldly, realms of the imagination which are nevertheless firmly rooted in the lived reality of the poets and their contemporaries. We too, when we read these poems, may feel simultaneously a sense of being transported to a world apart and of being seized upon by the poem's address in the here and now of reading. The fiction of occasion is proposed as a new conceptual tool for understanding how these poems produce such problematic presences and what varieties of experience they make possible for their readers. The fiction of occasion is defined as a phenomenon whereby a poem is fictionally framed as part of a material event or 'occasion' with which the reader is invited to engage through the medium of the senses. The book explores this concept through close readings of key authors from the corpus of first-person poetry written in Greek and Latin between the 3rd century BCE and the 1st century CE, with a focus on Callimachus, Bion, Catullus, Propertius, and Horace. The ultimate purpose of these readings is to move towards developing a new vocabulary for conceptualising ancient poetry as an embodied experience.