Stoicism was a popular strand of philosophy in the ancient world, originating in Athens around 300 BC. Among its chief tenets was the insistence that a true philosopher should be in total control of their emotions, accepting hardship and death without complaint. Clerval repeats the popular account in which famous follower Cato the Younger, a politician in the 1st-century BC, broke his stoical facade with a heartfelt display of grief at the funeral of his beloved half-brother Quintus Servilius Caepio.
Online edition of 'Cato: A Tragedy in Five Acts' by Joseph Addison, (1713)
A description of the Alps from Canto III of George Byron's semi-autobiographical poem Childe Harold's Pilgrimage (LXII). This is the first of several strange instances in Frankenstein of characters quoting from works which, while well known to Mary Shelley, had not yet been written at the time the story is set (See notes to page 75, page 104, and page 130)
Online edition of Lord Byron's 'Childe Harold's Pilgrimage', (1812-1818)
Frankenstein here references a passage from Chapter 9 of the Gospel of Mark, in which Christ describes the wicked undergoing eternal torment in Hell "Where their worm dieth not, and the fire is not quenched". The novel's re-wording is identical to that found in 18th-century minister Matthew Henry's six-volume commentary, which fittingly interprets the immortal 'worm' as representing the sinner's "remorse of conscience and keen self-reflection".
Online edition of the 'Authorized King James Bible', (originally published 1611)
Online edition of Matthew Henry's 'Concise Commentary on the Whole Bible', (originally published 1706)
This lengthy quotation is from Percy Bysshe Shelley's Mutability, published in Alastor, or The Spirit of Solitude in 1816, well after the period in which the novel is set (See note to page 74)
From The Lyrics and Shorter Poems of Percy Bysshe Shelley, (J.M. Dent & Sons, Ltd., 1907):
We are the clouds that veil the midnight moon;
How restlessly they speed, and gleam, and quiver,
Streaking the darkness radiantly!--yet soon
Night closes round, and they are lost forever:
Or like forgotten lyres, whose dissonant strings
Give various response to each varying blast,
To whose frail frame no second motion brings
One mood or modulation like the last.
We rest.--A dream has power to poison sleep;
We rise.--One wandering thought pollutes the day;
We feel, conceive or reason, laugh or weep;
Embrace fond foe, or cast our cares away:
It is the same!--For, be it joy or sorrow,
The path of its departure still is free:
Man's yesterday may ne'er be like his morrow;
Nought may endure but Mutability.