This is sort of a slightly undersized coffee-table book (lots of white space, sidebars, illustrations), but the author is a real academic.
Anyway, here’s a thought: After reading about these bloodthirsty, sex-crazed tyrants, it occurs to me that perhaps all that would have given Christianity some reactive appeal. (Also, it should caution us Westerners from reflexively looking down on non-Western countries just because their leaders had similar foibles.)
One tidbit from the book (41): Herod Agrippa was involved in the burial of Caligula — he had been sent by his grandfather to Rome where he was in the imperial court.