I haven't written this up yet.
The bare bones information is this:
Zeljan is ruled by Zelis 4th.
Not so long ago, there was a brigand leader named Zelis. He and his band of followers preyed on travellers on the road from Caljanat to Jantheny. The brigand camp was a little way off that road.
Zelis was good at armed robbery, but not all that good at sociology. He probably never understood how it was that his brigand camp morphed into a fortified city and he morphed from a brigand leader into mayor of that city. A good dictionary might have advised him that the single word which means successful brigand is politician.
Zelis 4th is the great-grandson of Zelis the Brigand. The people of Zeljan take it more or less for granted that city offices such as mayor are inherited.
Despite its historical origin, you are no more likely to be robbed in modern Zeljan than in any other city.
A couple of miles outside modern Zeljan, there are the ruins of an old city. No-one knows its proper name, so it is called Old Zeljan. The city itself was abandoned many centuries ago, but its marketplace was still in use until the days of Zelis 1st. Farmers used to go there once a week to exchange agricultural produce. Since Zelis 1st became respectable and opened a marketplace in Zeljan, the farmers have gone there instead.
Sages in Atlantis will tell you that Zeljan is simply the modern name for the old city, and that Zeljan is actually the oldest city on the continent. Sages are always making stupid mistakes like that.
There are rumours that Old Zeljan is haunted. The rumours may or may not be true (that's up to you).
Rumour: Somewhere north-east of Xenby, villagers are being attacked by goblins. Or hobgoblins. Or something like that. The villagers would welcome anyone who likes killing goblins, or hobgoblins, or whatever they are.