Quote Investigator is a website that fact-checks the reported origins of widely circulated quotations. According to Wikipedia, the website was started in 2010 by Gregory F. Sullivan, a former Johns Hopkins University computer scientist who runs the site under the pseudonym Garson O’Toole. Many of the quotes examined on the site are emailed to him by readers.

O’Toole is also the author of a book entitled Hemingway Didn’t Say That: The Truth Behind Familiar Quotations. The New York Times reviewed the book in 2017 and confirmed that Gregory F. Sullivan is indeed the author of the website.

Sullivan “tries to track down correct information about the provenance of sayings by utilizing the massive text databases that are being constructed right now along with other quotation history resources.”

The site reports that it had more than 4.2 million visitors between June 1, 2021 and May 31, 2022. It’s a free site.

The Library of Congress also hosts a list of quotation reference websites. However, many of these websites, unlike Quote Investigator, do not cite an original source. Even so, it is a good resource.