 Fantosme was a contemporary and often claimed to be an eye-witness of the events he describes, but another probable source is Richard of Ilchester, his bishop.His work is in general a reliable historical source.A Goliardic Latin poem defending the incarnation and atonement of Jesus Christ and which is preserved in many manuscripts is entitled in one near-contemporary source as "Rithmus Jordanis Fantasmatis" and it is likely that the author was Fantosme, or at least believed to be Fantosme.