From A Wiki of Ice and Fire
The mud-and-blood towns of the Basilisk Isles teem with escaped slaves, slavers, skinners, whores, hunters, brindled men, and worse.
Life on the islands is described as nasty, brutal, and often short. The isles are hod, humid, and swarming with stinging flies, sand fleas, and bloodworms, making them unhealthy for both man and beast.
- The Isle of Tears, located in he bay off the northwestern coast of Sothoryos were Gogossos once stood
- The Isle of Toads, located southwest of the ruined city of Zamettar, home to a mysterious toad-shaped idol made entirely of oily black stone
- The Isle of Flies, located on the western end of the isles
- Howling Mountain
- Talon, a large, claw-shaped island north of the Isle of Tears, home to the corsairs' slave market and Barter Beach.
- Skull Isle, the northernmost of the Basilisks, located in the Summer Sea, exactly north of Zametttar, where the corsairs deliver skulls to some dark god.
- Ax Isle, located northeast of Zamettar and southeast of Skull Island.
Ruins on the Isle of Tears, the Isle of Toads, and Ax Isle indicate the presence of an ancient civilization, now lost, established during the Dawn Age. Yandel speculates the inhabitants of the Isle of Toads may have a link to this vanished people. 
The Ghiscari Empire once founded a city on the Isle of Tears, naming it Gorgai, and held it for between two to four centuries until the Valyrian Freehold captured it during the Third Ghiscari War and renamed it Gogossos. The dragonlords used it as a penal colony for the worst criminals. Yandel reports that in its dungeons, torturers devised new torments while in its flesh pits, the darkest blood magic was practiced, as beasts were mated to slave women to bring forth twisted half-human children.
During the Rhoynar migration, Nymeria first led her people through the Summer Sea, pausing at the Basilisks to take on fresh water and provisions, only to be attacked by the corsair kings of Ax Isle, Talon, and the Howling Mountain, who put two score ships to the torch and carried off hundreds into slavery. Afterward, the corsairs offered to allow the Rhoynar to settle on the Isle of Toads, provided they gave up their boats and sent each king thirty virgin girls and thirty pretty boys each year as tribute. Nymeria refused and took her fleet to sea one again.
Gogossos outlived the Doom of Valyria and waxed rich and powerful during the Century of Blood, some calling it the "Tenth Free City", thanks to slavery and sorcery. Its slave markets became as notorious as those of the cities of Slaver's Bay. However, seventy seven years after the Doom a terrible plague, the Red Death, emerged from the slave pens of the city and swept across the Isle of Tears and then the rest of the Basiliks. Nine of every ten men died screaming.
For a century thereafter, the isles were shunned. It wasn't until the coming of corsairs that men returned to the Basilisks again. The Qartheen pirate Xandarro Xhore was the first to raise his banner, using the stones the found on Ax Isle to erect a grim black fort above his anchorage. He was followed by the men of the Brotherhood of Bones, who settled at the western end of the archipelago upon the Isle of Flies. From these bases, these pirates were in perfect position to attack the merchant ships rounding the smoking remains of the Valyrian peninsula. Within a century, nearly every Basilisk was home to a corsair nest.
Even though the Broteherhood of Bones is long forgotten and all that remains of Xhore is his fort, the corsairs still haunt the Basilisk Isles. Periodically, mostly once each generation, fleets are sent to the islands to clear out these pirates. Most of these fleets hail from Volantis, often in alliance with other Free Cities. Some of these ended in failure for the corsairs, forewarned, fled. Others have led to hundreds being hanged and scores of ships either seized, sunk, or put to the torch. Meanwhile, one of these raids ended in infamy, when the Lysene captain Saathos Saan, commanding a fleet sent to destroy the corsairs' strongholds, turned pirate himself and reigned as "King of the Basilisk Isles" for thirty years.
Despite the outcome of these efforts, corsairs resume their activities after a time. Their towns sprout suddenly, only to be quickly abandoned. Out of these pirate lairs, Port Plunder is the most famous, celebrated in song and stories, yet it can't be found on any map, for there have been at least a dozen Port Plunders on as many of the Basilisks. Whenever one is destroyed, or abandoned, another is founded, only to be destroyed or abandoned in turn. The same happened with Sty, Whore's Gash, Black Pudding, and many others.
A Feast for Crows
A Dance with Dragons
After returning to Meereen, Daario Naharis tells Daenerys Targaryen that among the turncloaks who have come over to her side is an axeman from the Basilisk Isles, a brute bigger than Strong Belwas.
Victarion Greyjoy gives Red Ralf Stonehouse the Iron Fleet's swiftest ships to sail the corsair's road along the northern coast of Sothoryos and seek provisions through the iron price from towns in the Basilisk Isles. Victarion gave orders to reunite off the southern tip of the Isle of Cedars; only nine of the ships that had sailed with Ralf turn up, with Ralf himself among the missing.
References and Notes
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 The World of Ice and Fire, The Basilisk Isles
- ↑ 2.0 2.1 A Dance with Dragons, Chapter 56, The Iron Suitor (Victarion 0).
- ↑ 3.0 3.1 The World of Ice and Fire, Ten Thousand Ships.
- ↑ A Feast for Crows, Chapter 21, The Queenmaker.
- ↑ A Dance with Dragons, Chapter 11, Daenerys.
- ↑ A Dance with Dragons, Chapter 36, Daenerys.
- ↑ A Dance with Dragons, Chapter 67, The Kingbreaker (Barristan III).