Apparently, some royal prince is getting married soon in the UK. I am afraid I have no interest in the event, though it seems that lots of people will enjoy it, so that is splendid.
Something that interested me in this connection was an article by Marina Hyde in the on-line Guardian (here) which discussed some of the absurd ways that people in the UK have chosen to celebrate the royal wedding. In describing someone from Bristol who has decided to have his teeth tattooed, thus eclipsing the efforts of someone else who has made a commemorative statue out of toothpicks, she ended her article with the phrase 'sic transit gloria imbecili'.
Now, I admit that I did not know what this means, so I looked it up. Apparently, the original phrase is 'sic transit gloria mundi', which means "thus passes the glory of the world", meaning that everything we encounter is temporary (see the Wikipedia entry here). But the writer has changed mundi ('world') to imbecili ('idiots'), so the phrase instead comes to mean "the glory of idiots is transitory".
This is an allusion, and the writer expects people to know the original phrase in order to appreciate her clever play on words. If you don't know the original (and if you don't have any knowledge of Latin), then it remains completely opaque. But, thankfully, in the modern world it is quite easy to look things up.
It is also possible that the modified wording is commonly used but I am too far out of touch with usage in the UK to be aware of it. But a Google search of 'sic transit gloria imbecili' only offers the occurrence in the Guardian article, which suggests that it is indeed not a common phrase. A search in the COCA corpus (here) for the phrase 'sic transit gloria' returns 10 hits. 7 of them are followed by mundi, and none of the other 3 have imbecili, which confirms it is not a common phrase, at least not in the USA.
"Artist=President Barack Obama"
20 hours ago