The Elves of this house wore vestiture of many vivid colors, since The Heavenly Arch referred to the rainbow. Along with those of the House of the Swallow, these Elves were the finest archers in Gondolin, and some of the greatest swordsmen. Each of their weapons was set with bright jewels, and their shields were blue, bearing in the middle seven precious minerals of color.
During Gondolin's fall, bowmen of the Heavenly Arch fired many volleys of arrows upon enemy orcs at the city's northern walls. As the odds of the onslaught turned slowly against the Gondolindrim, these defenders retreated to the Square of the Palace, along with others, where Tuor gathered them. By the end of the battle, few warriors of the House of the Heavenly Arch had escaped and lived on.