Why was Saint Paul beheaded?

Much of Rome had burned in an immense fire in nthe year 64 AD., some say it was intentionally started by Emperor Nero who wanted to rebuild the city in his own vision. To deflect the blame he decided to blame the Christians for the blaze. He already considered the Christians a threat and irritation so used this excuse to begin a mass persecution of the Christians. Paul was already in prison at the time so was readily available to be executed.