A number of things intrigue me about Gaudete.

Although it was first published in 1582, it's generally referred to as being a medieval folk carol which if true, implies it must be at least 100 years older than that. Is there any consensus about how old it's likely to be?

It was first published in Finland, but in a collection that included songs from all over northern Europe, and as it's in Latin, it could originate anywhere. Is there any consensus about where it's likely to have originated?

Does anyone know what "Piae Cantiones" (the title of the book in which it was first published) actually means? Google translate is no help! I assume it must mean something like "Song collection"?

Was it reasonably common for medieval folk carols to be written in Latin? Presumably ordinary people wouldn't have been able to understand or join in with them, only the elites. I realise that the Mass was said in Latin, but as I understand it, ordinary people didn't understand the words of the Mass either, although they'd have been told the broad meaning.

Given that ordinary people wouldn't have been able to sing a Latin
carol, would monks perhaps have walked through the town squares singing it in procession? Might the ordinary people have joined in with the choruses? Would someone have translated the verses for them?

Dave