Prolepsis has two great advantages. First, it has mystery, but not too much. When a poem opens with a pronoun, a little bit of your mind thinks to itself: “What? What the hell’s going on? Who? Who are they?” For a moment it weeps and wonders, but only for a moment, because a few words later, before the full stop is even upon us, you find out that they are the old masters, or your mum and dad, or the days of wine and roses.