Pulman's dinner meeting of the Germanicus avengers provides a convenient opportunity for Agrippina to relate the gory details of Germanicus' demise.

That the suspected poisoning was countered by Agrippina's culinary skills comes from Graves alone. That Germanicus had a slight recovery is also found in Tacitus.

As for the witchery, Pulman has Agrippina quote Graves almost verbatim. She presents as evidence: the naked and decaying corpse of a baby with a belly painted red and horns tied to the forehead, the corpse of a cat with rudimentary wings growing from its back, the head of a Negro with a child's hand protruding from its mouth, a lead tablet bearing the name of Germanicus, cock feathers smeared with blood, the disappearing letter name game and the exploitation of his irrational fear of the Number 25. Pulman even feels the need to tamper with Graves' horror hall of fame: the child's hand was white, the name Germanicus was written on the skull of an ass, the word Rome appeared spelled upside down (not backwards) and his arithmophobia was focused on the Number 17. Curiously he omits the midnight appearance of the big black cock with a golden ring in Caligula's room.

Apparently the evidence in the ancient sources wasn't gruesome enough. Suetonius mentions spells and potions used against Germanicus which prompted him to formally renounce his friendship with Piso. Dio states that curse tablets and bones of men were found in the home. Tacitus' evidence list is a bit more fulsome: disinterred bodies, incantations and spells, the name of Germanicus on leaden curse tablets, half burned cinders smeared with blood, and other horrors to damn a soul to Hades. So, we must assume that Graves felt compelled to improve upon Tacitus, filling in the blanks of those "other horrors."