Commentary Par XX 108

What is perhaps most surprising about Trajan's reward is that it was won not by his hope, but by that of Pope Gregory.  We are reminded of the fate of those in Limbo (where, we assume, Trajan was first lodged), who exist (according to [Inf IV 42]) longing for a better lot, if without hope for it (sanza speme).  Gregory's hope 'conquered' God on Trajan's behalf; the emperor himself, the evidence that we gather from Limbo would seem to assert, was hopeless.