It's probable that more than a few of these bamboo tubes were imperfectly sealed and, instead of bursting with an explosion, simply went skittering out of the fire, propelled by the rapidly burning gunpowder. Some clever observer whose name is lost to history may have then begun experiments to deliberately produce the same effect as the bamboo tubes which leaked fire.
Certainly by the year 1045 A.D. -- 21 years before William the Conqueror would land on the shores of England -- the use of gunpowder and rockets formed an integral aspect of Chinese military tactics.
A point of confusion arises tracing the history of rocketry back before 1045. Chinese documents record the use of "fire arrows," a term which can mean either rockets or an arrow carrying a flammable substance.
By the beginning of the 13th Century, the Chinese Sung Dynasty, underpressure from growing Mongolian hordes, found itself forced to rely moreand more on technology to counter the threat. Chinese ordnance experts introduced and perfected many types of projectiles, including explosive grenades and cannon. Click here for more details...