A helpful reader sent me a reference for one of the unsourced statements in the Citation Needed (January) post! So was it true, or not?
In January 2020, the Wikipedia article for Xochicalco included the following statement:
Alexander von Humboldt published illustrations and a description of Xochicalco in 1810.[citation needed]
A sharp-eyed reader (who has visited Xochicalco!) tracked down Views of the Cordilleras and Monuments of the Indigenous Peoples of the Americas, a book by Humboldt which does include a plate and description for Xochicalco — so it does seem to be true!
Reading the description more carefully, I can see that Humboldt did not actually visit Xochicalco, which seems like an important detail:
The drawing of the relief on the lowest terrace was copied from an engraving published in Mexico City in 1791. I did not have the opportunity to visit this remarkable monument myself.
I expanded the statement in the article to include the more specific information:
In 1810, Alexander von Humboldt published a description and illustration of Xochicalco, based on Alzate’s description and an engraving published in Mexico City in 1791.
With the statement amended, I added the reference by clicking the “Cite” button and filling out the form for citing a book:
After inserting the citation, I published the changes with a descriptive summary and the #1lib1ref hashtag:
The previously iffy statement now has a citation to a reliable published source — the article is improved!