Desert Bus monitoring has taken up a ton of my time, so I've been away from here for most of it. Sorry about that. But it should be wrapping tomorrow night (barring anything truly mind-poppingly insane concerning donations).
So while you wait (and hopefully donate)... I'll leave you in the capable hands of John Green, who in this video, that I won't embed because linking it leads you to other Mental Floss videos, explains the origins of 62 common last names. Because last names were not always a thing. You may hear in ancient times about people getting called, oh, say, 'Jesus of Nazareth'. That's how things got done back then a lot of the time: the first name followed by some sort of descriptor (Alexander the Great being another one). Actual last names started trickling in at different times in different regions, and they had to start coming from somewhere. As you'll see. Anglo-Saxon, for example, came about in what you'd probably call the mythical Knights Of The Round Table era, the 1300-1400's, and names from that region have a way of reflecting the culture of the time.