Tacitus is the major source for the particulars of Piso's trial. Tiberius' speech in the Senate is an extreme epitome of the one found in Tacitus- on the whole accurate, but lacking in nuance. Pulman has Castor, as prosecutor numero uno, list the charges against Piso in his opening statement. In Tacitus, Drusus (aka Castor) was present for the trial, but took no part in the prosecution. Fulcinius Trio actually begins the trial with stale old charges about Piso's Spanish improprieties. Graves, in an odd twist, has these Spanish accusations brought forward by a nameless designated doofus as a Tiberian ploy to run out the prosecution clock.