An Chongrong's father served as the military commander of Zhenwu's cavalry and infantry in the Later Tang Dynasty, and Chongrong grew up among soldiers, becoming strong and skilled in horseback archery, eventually appointed as Zhenwu's border patrol commander.
When Shi Jingtang raised an army in Taiyuan, he sent a deputy general named Zhang Ying to sneak into Zhenwu and request that An Zhongrong raise his own troops to assist in the grand undertaking. An Zhongrong's mother and brother deemed the plan too risky and wanted to kill Zhang Ying to prevent An Zhongrong from rebelling against the Later Tang.
An Chongrong rushed into the garden and declared, "Man proposes, Heaven disposes. Let me consult the heavens through archery before deciding whether to kill Zhang Ying." He planted an arrow in a wooden stake a hundred paces away, then looked up and prayed, "If Lord Shi is destined to become the Son of Heaven, let my first arrow strike true." His bowstring twanged, and with a sharp crack, the arrow in the stake snapped cleanly in two. An Chongrong placed another arrow in the stake and prayed again, "If I am to become a military governor after joining Lord Shi, let my second arrow also hit its mark." Another arrow flew, and the second shaft was also split in two.
Zhang Ying escorted An Zhongrong to Taiyuan. Shi Jingtang soon ascended the throne as emperor, founding the Great Jin dynasty. To honor An Zhongrong for leading his thousand-strong cavalry patrol to defect to the Great Jin, Emperor Gaozu of Jin appointed him military governor of Chengde Army.
Shi Jingtang groveled before the Khitan, calling himself the "Son Emperor" in their presence and sending regular tribute of grain and goods. An Zhongrong fumed, "Bowing to barbarians while squeezing our own starving people for supplies to appease the Khitan—this is the eternal shame of the Great Jin!" Whenever Khitan envoys passed through his territory, An Zhongrong gave them nothing but cold stares, and on several occasions, he secretly had their messengers seized and executed.
The Tuhun tribe, unable to bear the tyranny of the Khitans, fled from beyond the Great Wall to seek refuge with An Zhongrong. The Khitan ruler pressured Emperor Jin to force An Zhongrong to hand over the tribe. An Zhongrong declared, "Is the Son of Heaven truly born to the role? Any commander with strong troops and horses can become emperor." He gained the support of the military governor of Youzhou and prepared to rebel, aiming to contend for the realm with Shi Jin. His mother advised against it. An Zhongrong pointed to the dragon head atop a flagpole in the distance and said, "If I am destined to rule, let me shoot an arrow through the dragon's mouth." He drew his bow and, with a single shot, struck the target perfectly.
An Chongrong led his army toward Bianjing. But his vanguard defected, the advance stalled, and Chengde suffered years of drought and locust plagues, leaving the army short of supplies. That winter, with relentless snow and wind, the soldiers lacked warm clothing and morale collapsed. An Chongrong lost all advantage of his "strong troops and sturdy horses" and had to retreat to defend Chengde.
The Jin army breached Chengde, and An Chongrong was killed.
"Strong soldiers and sturdy horses" describes a powerful military appearance and an army full of combat effectiveness.
Source: *New History of the Five Dynasties*, "Biography of An Zhongrong"
Meaning of the Idiom: Later, the Chinese idiom "兵强马壮" came to describe how a powerful military appearance and an army full of combat effectiveness.