The popular line paraphrases a passage in Book 4, chapter 14 of De regimine principum (On the Government of Rulers). Aquinas began that treatise, but Ptolemy of Lucca wrote Book 4 when he completed it around 1300. Ptolemy credits the sewer image to Augustine, yet the genuine Augustine passage (De ordine 2.4.12) mentions no sewer. See Wikiquote ↗.
“Prostitution in towns is like the sewer in a palace; take away the sewers and the palace becomes an impure and stinking place” is often credited to Thomas Aquinas, but it paraphrases Ptolemy of Lucca, De regimine principum, Book 4, ch. 14 (completed around 1300), who credits the image to Augustine. Via Quotle.info
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In context
Evoking the world of Ptolemy of Lucca — Dominican friar, historian & bishop of Torcello. Theme: "Prostitution in towns is like the sewer in a palace; take away the sewers and the palace becomes an impure and stinking place". Atmospheric and restrained, cinematic directional light, a muted period-appropriate palette, fine grain and texture. Compose with generous empty space for the quote and a small credit line. No lettering in the image itself.
Minimalist
Minimalist editorial slide for the quote "Prostitution in towns is like the sewer in a palace; take away the sewers and the palace becomes an impure and stinking place". Clean background, a single muted accent color, generous negative space, subtle paper or linen texture, no literal illustration — let the words carry it. Reserve clear space for a serif quote and a small credit line. No lettering in the image itself.
Provenance
Where the line really comes from
Work
De regimine principum (continuation of Aquinas’s De regno), Book 4, ch. 14
Author of this part
Ptolemy of Lucca (completed around 1300)
Translation
James M. Blythe, On the Government of Rulers (University of Pennsylvania Press, 1997), 4.14.6
Popular English wording
Unsourced paraphrase, not Blythe’s text
Unde Augustinus dicit, quod hoc facit meretrix in mundo, quod sentina in mari, vel cloaca in palatio: tolle cloacam, et replebis foetore palatium: et similiter de sentina: tolle meretrices de mundo, et replebis ipsum sodomia.
Latin original, Book 4, ch. 14
Blythe’s English, as quoted on Wikiquote ↗, reads: “Thus, Augustine says that a whore acts in the world as the bilge in a ship or the sewer in a palace: ‘Remove the sewer, and you will fill the palace with a stench.’” The phrases “in towns” and “impure and stinking place” appear in neither the Latin nor that translation.
Wikiquote’s Thomas Aquinas page ↗ lists the line as Misattributed. It identifies the source as Ptolemy of Lucca’s continuation of De regimine principum (Blythe translation, 1997, 4.14.6), and notes that only Book 1 and the first four chapters of Book 2 are by Aquinas.
The catalog record for Blythe’s translation ↗ (University of Pennsylvania Press, 1997) says Ptolemy finished the work around 1300, completing a treatise long attributed to Aquinas.
Wikipedia ↗ says Ptolemy completed De Regimine Principum after Aquinas died and wrote Books 3 and 4.
The popular English wording is an anonymous paraphrase with no identifiable source, so we assert no rights status for it. The Latin original (completed around 1300) is long in the public domain. Blythe’s 1997 English translation (University of Pennsylvania Press) is a modern rendering still in copyright.
Rights status is our research, not legal advice — and copyright varies by country and edition. For commercial or published use, confirm with the rightsholder. See terms.
Fact-check
How Aquinas got the credit
The line is pinned on Thomas Aquinas because the treatise it comes from began as his. Aquinas left De regimine principum unfinished, Ptolemy of Lucca completed it, and the whole work long circulated under Aquinas’s name.
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Popular attributionThomas Aquinas Wrong
Aquinas did not write the part of the treatise that holds the passage. Wikiquote ↗ notes that the work mentions the 1298 coronation of Albert I of Habsburg. Aquinas died in 1274 ↗.
✓
Actual author of the passagePtolemy of Lucca Source
Ptolemy wrote Book 4, chapter 14, where the bilge-and-sewer comparison appears in the Latin text ↗.
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Credited by PtolemyAugustine of Hippo Embellished
Ptolemy introduces the image with “Augustinus dicit”. But Wikiquote ↗ gives what Augustine actually wrote in De ordine 2.4.12: “Remove prostitutes from human affairs and you will unsettle everything on account of lusts.” That passage has no sewer and no palace.
✓The image of the sewer in the palace is Ptolemy of Lucca’s elaboration of a milder line from Augustine. The tidy English version credited to Aquinas is a later paraphrase of Ptolemy (Wikiquote ↗).
Context
What the passage was arguing
In the Latin text ↗, the sentence comes in a discussion of soldiers and marriage. Ptolemy reports that Aristotle rejects Plato’s view that men devoted to war should not marry. He then gives his reasoning: relations with women are a lesser evil than falling into “vile vices”. The sewer comparison is offered in support of that point.
So the passage is a medieval “necessary evil” argument for tolerating prostitution, put in Augustine’s mouth. It is neither a statement by Aquinas nor Augustine’s own words.
Tolle cloacam, et replebis foetore palatium.
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Filed under
More provenance-checked quotes on the same theme, each with its reuse status.
c. 1236 – c. 1327 · Dominican friar, historian & bishop of Torcello
Ptolemy (Tolomeo) of Lucca was a Dominican friar who was a friend and confessor of Thomas Aquinas. In 1318 Pope John XXII made him bishop of Torcello. After Aquinas died, Ptolemy completed Aquinas’s unfinished treatise on kingship, De regimine principum, and wrote Books 3 and 4 himself. Because the finished work long circulated under Aquinas’s name, Ptolemy’s words, including this passage, have often been credited to Aquinas.
For writers & researchers
Cite this
Original source
Ptolemy of Lucca, On the Government of Rulers: De Regimine Principum, with portions attributed to Thomas Aquinas, trans. James M. Blythe (Philadelphia: University of Pennsylvania Press, 1997), 4.14.6. Latin: Ptolomaeus Lucensis, Continuatio S. Thomae De regno, lib. 4, cap. 14, Corpus Thomisticum.
This verification page
Quotle.info. “Who really said ‘Prostitution in towns is like the sewer in a palace; take away the sewers and the palace becomes an impure and stinking place’?” Last verified 3 Nov 2026. https://quotle.info/who-said/prostitution-in-towns-is-like-the-sewer-in-a-palace-take/