Possibly useful period information

[igenlode]

Some stuff I stumbled across when looking for information on what letters in the 1640s actually *looked* like: https://honorandintrigue.blogspot.com/2017/11/early-modern-price-list.html
Note that this is for 1620s France rather than 1640s, but the relative prices at least should give some kind of idea...

Information on letters: https://honorandintrigue.blogspot.com/2016/12/envelopes-and-letters-in-17th-century.html