The Wall
The wall is a mystical force which surrounds the entire boundary of Qedivar, and rises over it in a dome-like shape. It's not precisely a dome, as Qedivar is closer in shape to a rectangle than a circle or oval, and scholars are reasonably certain the wall follows the ancient historical boundaries of the Dutchy.
Physical Properties
The wall itself is semi-permeable. Weather and inanimate objects generally pass through it, but nothing imbued with a spell effect can pass through it. No magical spells or items with spell effects. It's difficult to know if it's magic per se which fits the barrier, as Qedivarians with little or no magic can't pass the barrier, either.
In general, if a creature is capable of speech or tool use it can't pass the barrier (A pod of dolphins was trapped in the Southern Sea and their descendants aid the Merlings to this day.) If the creature is magical: a non-sentient construct, a magical monster or other such creature it cannot pass. However, birds, rodents, normal animals like deer or boar seem to pass through it fine. Certainly inanimate (yet potentially magical) things like rain, lightning, sunlight, pass through the wall with ease.
There is also a physical stone wall around some parts of the Dutchy where the landscape allows. This stone/physical wall is quite high, such that it intersects the slope of the magical wall (and can't be climbed by anyone inside Qedivar). Other parts of the wall are unblocked because the environment is impassable, such as the Wyrmcave Mountains, the Southern Sea, and quite possibly somewhere in or near the border of the Lytchwood.
History
No one in Qedivar remembers precisely when the wall went up or why. It's pretty settled in legend that the first to Dukes after the Wall were Duke Prescott the Illuminated and his daughter, Priscilla the Mighty. However those are ancient legendary tales, over one thousand years old and the records have not been well kept or clear.
Amongst Qedivarian historians there are two theories.
First, that the wall was put up by ancient Qedivarian Wizards using their Automaton slaves as a source for the magical feat. That these ancient wizards died in the process, passing their freedom on to the automatons, and succeeding in protecting Qedivar from the horrors' of the Outside.
Many others argue that this theory is incorrect. There's no evidence of ancient lost wizards (there are legends of ancient not-lost wizards); the automaton rise to freedom is well documented and more recent. Also these ancient wizards didn't document how the Wall was built and yet the Dukes have always researched it with no real success. Finally, there's the physical wall which isn't accessible by anyone inside -- wouldn't we want to keep an eye on things?
These historians argue that someone outside Qedivar built the wall and that Qedivar is, essentially a prison. They, however, cannot cite the reason for the imprisonment. As for the argument about watching the outside -- the outsiders don't seem to be watching Qedivar.
Most lay Qedivarians thing the wall is there to protect them. Few want to believe they are imprisoned. Some even argue that there is nothing outside, that the outsides destroyed themselves and Qedivar was protected from the calamity by the wall -- no matter who put it up.
Recent Developments
As a last word on the wall, some scholars, including Duke Rosaline believe the wall is weakening. Rosaline has a project to send investigators to the four edges of Qedivar to check the wall and the goings-on there to see if that is correct. It could be a great boon to reconnect to the larger world: resources are finite within their bubble. But it could also be a great calamaty depending on what is out there, and how they feel about Qedivarians.
Surely, if the wall were to fall it would be a turbulent time in Dutchy.