Script editor Donald Tosh rewrote much of the script delivered by John Lucarotti. In a monograph on "The Massacre", James Cooray Smith argues that the Doctor's similarity with the Abbot of Amboise was inspired by a real historical event, the impersonation in 1562 of the Abbot responsible for Marmoutier Abbey in the commune of Amboise by a man called Chastillon, who was later executed. He suggests that Lucarotti's original script (which no longer exists) involved the Doctor extensively impersonating the Abbot with the audience's connivance, whereas Tosh's preference was for the audience to be left unsure whether or not the Abbot was really the Doctor, leading to the disagreements between the two. There are conflicting accounts as to whether Lucarotti's name was removed from the credits at his request. Tosh is credited with co-writing the final episode, on which incoming script editor Gerry Davis was credited as script editor in his place.