From A Wiki of Ice and Fire
For the conflict with that same name, see Battle of the Ruby Ford.
The ruby ford is a crossing of the Green Fork of the Trident in the Riverlands. It is so named for the rubies that were knocked from Prince Rhaegar Targaryen's breastplate during the Battle of the Trident. A large, three-story inn with pale stone walls lies near the ford. There is no crossing of the Green Fork north of it until the Twins.
Robert Baratheon, who had raised a rebellion against the ruling House Targaryen dynasty led an army south and was met at a ford crossing the Green Fork by an army commanded by Prince Rhaegar Targaryen. Rhaegar had kidnapped Lyanna Stark, who was promised to Robert, making Robert a bitter enemy. When they came together at the ford they fought an personal battle, which Rhaegar lost when Robert drove his warhammer into the prince's chest, killing him. Adorning Rhaegar's breastplate was a three-headed dragon, the symbol of House Targaryen, done in rubies. The hammer blow knocked the rubies from his chest, spilling them into the ford, giving the ford its name.
A Clash of Kings
During the War of the Five Kings, the ruby ford changes hands several times. After his defeat at the Battle of the Green Fork, Lord Roose Bolton reclaims the ruby ford from the Lannisters along with the Crossroads Inn.
A Storm of Swords
References and Notes