Osbert was accused of murdering William , specifically by poisoning him through the communion chalice . A fellow cleric , Symphorian , who had been a chaplain of the deceased archbishop , brought murder charges against Osbert . Symphorian obtained a hearing on the charges at a royal council presided over by King Stephen of England at Michaelmas in 1154 , but Stephen 's subsequent death prevented a resolution . Osbert attempted to have the trial switched to an ecclesiastical court and was supported in his efforts by Archbishop Theobald of Canterbury . A trial was finally held in 1156 and Osbert 's accuser did not produce any witnesses , but Osbert was unable to prove his innocence , prompting the transfer of the case to a papal court . No record of any judgment exists , but Osbert apparently appeared before two popes , Adrian IV and Alexander III . A further appeal to the papal court was referred to papal judges @-@ delegate between 1175 and 1180 .