Where does 馬上 originate from? 馬上 can be used as an adverb that roughly means "at once" or "immediately", for instance in: 我馬上來幫你. It can also mean "on horseback". Where does the usage with the sense of "at once" originate from, and does it have anything to do with the other meaning of the adverb?
According to "互动百科", it's said that during China's ancient times, a general on horseback was on its way to perform an important task, but he was interrupted midtrip when a messenger caught up to him bringing him a message, which stated that the emperor was deathly ill. He immediately turned around and rode back to see the emperor without alighting from his horse (note: riding in the Forbidden City was strictly forbidden), hence the word "马上" to mean "immediately".