The writings of Cicero provide the majority of information regarding Gaius Verres, as well as a lot of information regarding Roman Sicily. There are other references to Verres, however, those are from later authors (Plutarch. Cicero. 7-8; Quintilian. 7.2.2; Pliny. Natural History. 34.6). It is more than likely that Verres is mentioned in such later sources through Cicero, but then if we had lost Cicero it may be the case that we would still be aware of Verres through these later sources, as we are regarding other pieces of information.