Sweet Saf, nicely nailed. Regarding a sociopath, isn't that what they called the likes of Caligula? 
Or is it narcissism?
Or both? 
Here's a test for sociopaths. In essence, it's a list of symptoms.
How to spot a sociopath
(Extracted from an article by Robert Matthews in the Sunday Telegraph Review, May 4th 1997)
While such personality disorders as psychopathy, paranoia and obsession/compulsion all have strictly defined criteria, psychiatrists are still struggling to decide precisely what constitutes a socialised psychopath.
One of the more obvious characteristics of socialised psychopaths is that they give the impression of talking "at" you. Prof Jeremy Coid describes it as like being regarded as a cardboard cut-out. "Even in a sexual relationship with them, you are still just an object for their personal gratification," he says.
The following questionnaire is based on research and experiences of socialised psychopaths. For each trait, decide if it applies to the person you suspect may be a socialised psychopath, fully (2 points), partially (1 point) or not at all (0 points).
1. Do they have problems sustaining stable relationships, personally and in business?
2. Do they frequently manipulate others to achieve selfish goals, with no consideration of the effects on those manipulated?
3. Are they cavalier about the truth, and capable of telling lies to your face?
4. Do they have an air of self-importance, regardless of their true standing in society?
5. Have they no apparent sense of remorse, shame or guilt?
6. Is their charm superficial, and capable of being switched on to suit immediate ends?
7. Are they easily bored and demand constant stimulation?
8. Are their displays of human emotion unconvincing?
9. Do they enjoy taking risks, and acting on reckless impulse?
10. Are they quick to blame others for their mistakes?
11. As teenagers, did they resent authority, play truant and/or steal?
12. Do they have no qualms about sponging off others?
13. Are they quick to lose their temper?
14. Are they sexually promiscuous?
15. Do they have a belligerent, bullying manner?
16. Are they unrealistic about their long-term aims?
17. Do they lack any ability to empathise with others?
18. Would you regard them as essentially irresponsible?
A score of 25 or above suggests strong psychopathic tendencies. This does not mean the person is a potential mass-murderer: socialised psychopaths are not mad, nor do they have to resort to violence. Even so, a close professional or emotional relationship with a socialised psychopath is likely to prove a damaging experience.
Here are the symptoms of narcissism:
Narcissistic personality disorder is characterized by dramatic, emotional behavior, which is in the same category as antisocial and borderline personality disorders.
Narcissistic personality disorder symptoms may include:
Believing that you're better than others
Fantasizing about power, success and attractiveness
Exaggerating your achievements or talents
Expecting constant praise and admiration
Believing that you're special and acting accordingly
Failing to recognize other people's emotions and feelings
Expecting others to go along with your ideas and plans
Taking advantage of others
Expressing disdain for those you feel are inferior
Being jealous of others
Believing that others are jealous of you
Trouble keeping healthy relationships
Setting unrealistic goals
Being easily hurt and rejected
Having a fragile self-esteem
Appearing as tough-minded or unemotionalDo you see the overlaps? The full piece about the personality disorder of the narcissist is here:
http://www.mayoclinic.com/health/narcissistic-personality-disorder/DS00652/DSECTION=symptoms
