In terms of sources, the Bible and Isidore of Seville (d. 636) form the lion's share of Pseudo-Jerome's allusions. It was once argued that Jerome's work had provided source material for Isidore, but this was disproven by Dalche (1984). These sources, and the others, are presented in a very paraphrased form and are rarely made reference to directly. The work is also filled with many fictional sources, which makes Jerome similar to Virgilius Maro Grammaticus, an Irish pseudo-grammarian of the 7th century. Whether there is any relationship between the two has been considered by Herren (1994), but the evidence is not conclusive in proving a certain, direct connexion between the authors.