Towards the end of the Eastern Han dynasty, Kong Rong had two friends with excellent sons: the elder, Wei Kang (courtesy name Yuanjiang), and the younger, Wei Dan (courtesy name Zhongjiang). Kong Rong held both in high regard.

In a letter to their father, he wrote: "Yuanjiang visited the other day; he possesses profound talent, shining intelligence, elegant demeanor, and great perseverance, truly an instrument for the world.

Zhongjiang visited yesterday; he is articulate, diligent, and sincere, a master to protect the family.

I didn't expect that a pair of bright pearls would emerge from an old clam so closely together."