Although the French Revolution is conspicuously absent from Frankenstein's narrative, it roughly spanned the 1790s when several literary references place the novel (See note to page 95), and was fresh in the memory of a Europe still reeling from its impact in Mary Shelley's time. In its early stages the Revolution was an ideological touchstone for radical observers, including Romantics like Wordsworth and Coleridge (See note to page 10), who saw established power as outdated and corrupt. For many however, breathless excitement gave way to horror at the frenzied executions of the 'Reign of Terror' and warmongering expansion of a new, militarised French Empire. Mary Shelley, who had seen firsthand the devastation left by the Napoleonic Wars on her trips to several European nations, shared the ambiguity of her peers towards an event which they felt, despite the "bloodshed and injustice with which it was polluted...produced enduring benefits to mankind"
Historical overview at the Encyclopædia Britannica
Analysis of how the French Revolution affected British politics by Mark Philp, (2009)
Online edition of 'History of a Six Weeks' Tour', Mary and Percy Shelley, (1817)