For a few centuries, the Harrigon's served the Smithes as loyal vassals from their castle of Bronzebridge. This was until King Marthew Smithe sent his son Prince Myrron to Bronzebridge with a decree; that the Harrigons would hand over all their land and their castle, and live at Hornworth to serve them as their elite Blacksmithes. Insulted by this decree, Lord Orroman's brother Cerrond refused. Prince Myrron and a few assassins crept into Bronzebridge, killing Cerronds as well as Orroman's two sons.
Cerrond discovered that Orroman was away from Bronzebridge, and took this opportunity to burn the castle down. Over the next few days, King Marthew attempted to track Orroman down, but was unsuccessful. Unbeknownst to him, Orroman had discovered the deed, and gathered together his closest friends and allies. In the dead of night, Orroman and his allies managed to siege the castle, killing King Marthew, his guards, and Prince Myrron.
Knowing that killing every Smithe would bring untold conflicts to their family, Orroman most of the surviving Smithes into exile, while taking both of King Marthew's daughters Allsa and Aryana as his wives, cementing his claim as King of the Forges. Along with Marthew's daughters, Orroman create a new sigil, taking the Hammer the Smithe's used. He also burned Hornworth to the ground, later building a new castle over the rubble, naming it Smithestone.
The surviving Smithes fled to Essos, eventually moving back to Westeros sometime after Aegon's Conquest.