This is the 100th story of the revived Doctor Who series.
The Doctor remarks that Terileptils were involved in starting the Great Fire of London. This happened in the Fifth Doctor story The Visitation: Part Four (1982), which also involved The Doctor teaming up with a highwayman.
Among the handbills visible by the gallows is one advertising "A Tryal of Witches." This bill is in fact a replica of the actual cover of the pamphlet of that name describing the trial held before Sir Matthew Hale of two witches. The trial took place on 10 March 1662 (misprinted in the pamphlet as 1664) at Bury St. Edmunds in Suffolk, and this pamphlet was printed in 1682. The two witches were named Rose and Amy (the names of two of The Doctor's former companions).
The Doctor informs Me that she may come across Captain Jack Harkness in the future, given that his life, like hers, is indefinitely extended. The Doctor already expressed his dislike and avoidance of immortals in a conversation with Jack in Utopia (2007).
The Doctor states that he is "on record as being against banter". This is a reference to Robot of Sherwood (2014) when The Doctor chastises Robin Hood and his Merry Men for their lighthearted banter.