ISB ~ Revelation 13 v3

One of its heads:The seven heads of the beast represent seven Roman kings, according to 17:9-10. mortal wound …

healed:The wounded head is probably Caesar Nero, who committed suicide in June A.D. 68. He was the last of Julius Caesar’s dynastic line, and his death threw Rome into political chaos and civil war. Though many thought the Empire had ended with the demise of Nero, a new claimant gained control of the throne (Galba), and the Empire lived on. Others read this as an allusion to the Nero redivivus legend, an ancient belief the Nero would someday return and reclaim his authority as Roman dictator. See notes on Rev 13:18 and 17:10.