'Invirond round with ayrie mountaine tops': Marlowe's source for 'Doctor Faustus.'

While the English Faust Book (EFB) has been accepted as the source for Christopher Marlowe's 'Doctor Faustus,' the date of the earliest edition of EFB and its effect on the dating of the play is uncertain. A description of the town Trier in the play differs from the description in the EFB. A possible source in a description of Trent in another work suggests that Marlowe used an edition of EFB which had 'Trent' instead of 'Trier' and the name in the play was later changed. This supports a dating for the play before 1592.