Volley gun
The Ribauldequin was a medieval version of the volley gun. It had its barrels set up in parallel. This early version was first employed during the Hundred Years' War by the army of Edward III of England, in 1339. Later on, the late Swiss army employed it.
Volley fire
Although volley fire is most often associated with firearms, the concept of continuous and concerted rotating fire may have been practiced using crossbows since at least the Han dynasty as described in the Han-Xiongnu Wars in the Records of the Grand Historian, although it was not until the Tang dynasty that detailed illustrations appeared. During the An Lushan Rebellion the Tang general Li Guangbi successfully deployed a spear crossbow formation against the rebel cavalry forces under Shi Siming. In 756 Shi Siming raced ahead of the main army with his mounted troops to intercept Li Guangbi's Shuofang army near the town of Changshan. Li took Changshan in advance and set up his men with their backs to the town walls to prevent a sneak attack. The spearmen formed a dense defensive formation while 1,000 crossbowmen divided into four sections to provide continuous volley fire. When Shi's cavalry engaged Li's Shuofang army they were completely unable to close in on his troops and suffered heavy losses, forcing a withdrawal.