To my understanding, Scotland became a constituent nation in 1707 following the Acts of Union and Ireland in 1800 (or 1801?). . However, I'm having trouble understanding when Wales became a constituent nation. I understand that there have been a few laws changing borders and such and that Wales got its own devolved parliament in 1998, but surely before this, Wales wasn't technically still apart of England, was it? . I suppose one way to explain my question would be like this: Welsh people, for centuries, have recognised their land as "Wales" regardless of what laws have been in effect, but when could they describe their land as being "Wales" and have it be legally correct as opposed to it being technically "England"?
You might be interested in reading some earlier threads while waiting for a full answer. A question about Wales' four word-entry in the Encyclopaedia Britannica leads to some discussion between u/jbdyer and other users about the nation's status in the 19th century, and when asked about the status of Monmouthshire, the user u/Tiberius_1919 takes a longer perspective going back to the Middle Ages and forwards into modern-day administration. New answers by our users are appreciated, of course