- This page is a stub, to aid navigation - it contains information from a prequel pitch that hasn't formally aired. As such it should not be considered full "canon" to anything yet.
Zamettar was a major port city on the north coast of Sothoryos. It is located on a large river delta, the mouth of the mighty Zamoyos River. By the time of the War of the Five Kings, the city was in ruins.
Empire of Ash
Zamettar was originally built thousands of years ago by the old Ghiscari Empire, as it colonized the northern coasts of Sothoryos searching for slaves and riches. During the Fourth Ghiscari War, however it was captured by the Valyrians - and at the end of the fifth and final Ghiscari War, all the rest of their empire in Essos was conquered as well.
Over the centuries, Zamettar grew to become the wealthiest colony-city in the entire Valyrian Freehold, surpassed only by Old Valyria itself. It was located on the vital shipping lanes returning west from the Jade Sea rich in silks and spices - much as to the north, Qarth dominates the shipping lanes traveling east into it. Due to its central location in the Summer Sea, Zamettar grew into a diverse crossroads of many peoples, visited by trading ships from Yi Ti in the east and from the Summer Isles to the west.
Over time, Zamettar became the main hub of the political faction known as the Free Holders, the local elites from the provinces resisting further domination from the dragonlords in Valyria's capital.
In the books
Zamettar was first mentioned by name in a map included with the third novel, A Storm of Swords, in 2000, which listed it as in ruins. The closest anyone ever came to it in the narrative was in the fifth novel, when Victarion Greyjoy was sailing the Iron Fleet east to Meereen, but chose to lead them farther north past the Basilisk Isles rather than near the mainland, as "the dead cities rotting on that fervid, sweltering shore were best avoided, every seamen knew" (The Iron Suitor, ADWD).
The World of Ice & Fire sourcebook (2014) gave the first significant information about Sothoryos and Zamettar. The only physical description given of Zamettar itself is that it was a great "walled city", apparently to defend against dangerous wildlife from the jungles. Maps show that it was built on an island of the river delta, further aiding its defensive position.
The chapter on "Sothoryos" explains that Zamettar used to be a Ghiscari colony that the Valyrians captured, but gives no explanation of what happened to it - specifically how or even when it came to be in ruins by the time of the War of the Five Kings. Meanwhile, slightly north of mainland Sothoryos are the Basilisk Isles, where another city named Gogossos is actually said to have flourished for 77 years beyond the Doom before being devastated by a plague and abandoned, but resettled a century later by pirates.
The chapter on the Rhoynish Wars, which took place some 600 years or so before the Doom, contradicts the "Sothoryos" chapter. It explains how Nymeria led the Rhoynar refugee fleet south, where they were attacked by pirate-kings in the Basilisk Isles, so they continued south to mainland Sothoryos. The Rhoynar stayed there half a year, with Nymeria herself commanding their outpost in the ruins of Zamettar. Again, no mention is made of how exactly it fell into ruin, only that it had been abandoned for "a thousand years". Eventually the tropical diseases and dangerous wildlife inflicted so many losses that Nymeria decided they should leave again, striking out west across the sea.
The chapter on the Rhoynar doesn't match the Sothoryos chapter: if the Valyrians were still at the height of their power, having just conquered the Rhoynar, why would they have abandoned all of their colonies in Sothoryos? It's possible that a plague could have struck the mainland - but "pirate-kings" were apparently flourishing in the Basilisk Isles at the time. The "Sothoryos" chapter makes it clear that Gogossos was still ruled by Valyria itself up until the Doom, and that it survived that disaster intact. If the Basilisks were still habitable enough and plague-free that pirate-fiefdoms were flourishing on them, why would the Valyrians let them remain independent at all? As a threat to their shipping in the Summer Sea?
Empire of Ash may be retconning the chapter from The World of Ice & Fire on the Rhoynar and their Ten Thousand Ships, this is unclear. However, that chapter already introduced several contradictions which have yet to be reconciled. Co-authors Elio Garcia and Linda Antonsson themselves have pointed out that different chapters were written by Martin independently, as some of them do not match up with each other - particularly, the "Iron Islands" chapter, which was written last. Like the Iron Islands chapter, the discrepancies about Zammetar in different chapters may be information which Martin himself will later revise for the book continuity.