The River Coppers were a sellsail company that operated primarily out of the Narrow Sea. They claimed descent from the Rhoynar displaced following the Spice Wars with Valyria, but over the centuries its members have hailed from across the Known World.
They were hired by Illyrio Mopatis during the First Targaryen Invasion of Westeros, in which the company was eradicated, along with another sellsail group the Keepers of the Waves.