A World of Ice and Fire says Duskendale was Westeros’s principal port on the east coast before Aegon’s Conquest. Is it ideally suited to be geographically? Why not White Harbor or Gulltown? Or even Spicetown on Driftmark? For being the principal port Duskendale didn’t must much of an army to protect itself.

Well, Gulltown has access to the Vale, but that’s it – there’s no riverrine access to the Interior. White Harbor was fairly new as cities go, so less time for trade routes to develop. Spicetown is on an island out in the bay, so there’s less room for facilities and a limited local market – it’s better suited as an entrepôt than a final destination.

Duskendale has a good harbor and access to a fertile and productive hinterland, and it’s fairly close to the Blackwater Rush which gives access to the interior. It is a bit surprising that the more proximate harbors near Rosby and south of what’s now King’s Landing didn’t develop first, but with trade routes you definitely have a first-mover advantage.