The Duke of Yansheng "Duke Overflowing with Sagacity", sometimes translated as Holy Duke of Yen, was a title of nobility in China. It was originally created as a marquisate (侯, hou) for a direct descendant of Confucius during the Western Han dynasty. The 11th-century Song Emperor Renzong later elevated the 46th-generation descendant to the rank of duke (gong).
The dukes enjoyed privileges that other nobles were denied such as the right to tax their domain in Qufu while being exempt from imperial taxes. Their fiefdom had its own court of law and the power of capital punishment, although such sentences had to be ratified by the Emperor.