This came before the usage of 皇 to broadly mean emperor (i.e. during the Spring and Autumn period before the Qin dynasty), although it is used to describe the three mythical emperors. Here it's a clan name (氏), the common clan name of the kingdom of Song.
When recording names in historical records usually the given name as well as honorary name are given as well (honorary names of these figures are all recorded alongside these given names and are far more ordinary).
When recording names in historical records usually the given name as well as honorary name are given as well (honorary names of these figures are all recorded alongside these given names and are far more ordinary).