Thandrium

Thandrium was the capital city of the Asgali Empire for most of its history, from 212 CV until the empire's collapse in 844 CV. In that same year occurred the catastrophic sacking, burning, and destruction of Thandrium itself, leaving it ruinous and mostly depopulated. If the empire had survived, the city might have been rebuilt over many years and at great expense; but with the concurrent general disintegration of the Asgali state, it was impossible. The site was never resettled and remains an expanse of crumbling, overgrown ruins to this day. However, during the golden age of Asgali power, Thandrium was one of the biggest and most important cities in Orithea. It could never quite match the splendor of Amran, but it was reputed to come close. 
Thandrium stood astride a broad bend on the lower Helvander River, in north-central Modrinia, very close to the river's mouth and just a couple miles upstream from the site of present-day Hakoris. Thandrium and Hakoris were both built in this vicinity for the same reason: To be at the nexus of all the riverine trade moving throughout the Taefemach up and down the Helvander, and all the maritime trade routes spreading out into the Sarpic Seas and beyond. The importance of this nexus has always made the mouth of the Helvander a vital strategic and mercantile crossroads. 
However, in the centuries since the Asgali collapse, slow changes in the river's course have gradually moved the main channel some distance from where it was in ~800 CV. The remnants of what were once the great city's docks and waterfront now lie several hundred yards from the current riverbank, separated from it by an expanse of low, marshy ground covered in willow groves and reedbeds. This is one reason that Hakoris was founded a short distance downriver, closer to the Helvander's mouth, rather than on the same site as Thandrium. The other reason is that the site chosen for Hakoris is more defensible, which was a greater concern in the chaotic post-Asgali period than in Thandrium's heyday as the capital of a huge and stable empire. The two sites are close enough, however, that a great quantity of stones were salvaged from the ruins of Thandrium and used in the construction of Hakoris. It was quite easy to haul them down to the riverbank, load them into rafts, and float them a short distance downriver to where the Helvandrian League's new capital was being constructed.