How does the author use foreshadowing in Claudius the God and His Wife Messalina?

I, Claudius is narrated by Claudius during the final years of his life. Throughout his narration, Claudius hints at events that are yet to come, oftentimes with the help of sibyls, oracles or other methods of divination. His visit to the Sybil of Cumae, for instance, foretells of his becoming emperor, and a dream that his slave Briseis has describes how his succession would take place.

In Chapter Nineteen, Germanicus continues to excel militarily, and thereby gains enormous popular support. This concerns Tiberius who fears Germanicus may attempt a military coup; nothing could be further from Germanicus' simple devotion to Rome. Needless to say, the combination of a suspicious Caesar and a naive hero foreshadows a dim future for the hero.