The handwriting in some of these snippets, while sometimes difficult to read for one reason or another, is nonetheless beautiful: did everyone who wrote have such great handwriting back then? I'm looking at the piece in the Instagram post linked by the page, which begins, "honor of holding in their service". The lines are so straight, the letters are so uniform!
Widespread literacy is an extremely recent phenomenon. I highly doubt most people could write that well
> Sheldon Richman quotes data showing that from 1650 to 1795, American male literacy climbed from 60 to 90 percent. Between 1800 and 1840 literacy in the North rose from 75 percent to between 91 and 97 percent. In the South the rate grew from about 55 percent to 81 percent. Richman also quotes evidence indicating that literacy in Massachusetts was 98 percent on the eve of legislated compulsion and is about 91 percent today.