For Bishop Justus see PRVT 246. He was a successor of Helladius, and he was a bishop from 633 (he signed the canons of the fourth council of Toledo in 633) to 636 when he died. In the previous section of the text Ildefonsus mentions a certain Justus, a deacon who insulted his bishop Helladius, and after his death "lived as a bishop himself." There is a controversy as to whether Ildefonsus is referring to the same person - it seems, however, more probable that the wicked Justus from the preface is a separate individual.