Sorry if this is in the wrong place.

Why did humans begin to record time and how did the whole world agree on a standard (24hrs etc.). I know the romans made a 10 month calendar into 12 months, but where did the 10 month calendar come from, and how did the world all take on the 12 month standard.

I was recently reading a book on the Byzantine Empire because it is an area that I know little about despite my great interest in Rome. Now in the book the author mentions a woman by the name of Sichelgaita and states that she accompanied her husband on campaign and was actually in command of the right flank in various battles. Now I wonder is this true and did she fight in combat?

I live in a costal beach town along the east coast of New South Wales Australia, and the other day we were swimming and body surfing the waves and I thought and said to my mate 'do you think aboriginals ever swam at the beach and body surfed waves 30,000 years ago?' I don't know why but it's very hard to imagine!

Modern soldiers suffer from it, so it stands to reason that folks that had to kill up close and personal must have suffered from it as well right? I'm just wondering if it's mentioned anywhere.

I'm absolutely fascinated by cold war history, and I want to read as much as I can about these secret police entities.

Doesn't it make more sense than the 31st of December?

Was the maniple checkerboard formation in republican legions adopted and used to defeat the phalanx . All armies ussually faced each other in a battle line . uninterupted .. but did the maniple frontage with gaps allow the phallanx to bulge ? .. stopping where their was resistance and bulging forward where there was no resistance ? Then could a missile and pilum attack into the sides of the bulges allow legionaries to break into the sides of the phalanx ?

Today, I learned about the enacting of Martial Law in Poland during 1981-83. One of the things the wiki article mentioned that many Polish people think that the imposition of Martial Law was good because it prevented Soviet intervention. Now, I don't know much about Soviet history but I didn't think that the Soviet Union had the ability to intervene in other nations during the 80s, but did the Soviet Union have the ability to intervene in Poland during the early 80s?

Did they just hug the horse as flat as they could and hoped they didn't fall off?

I've read many times, both here and elsewhere, that the period following the fall of Rome, whatever you want to call it, did not in fact experience slower scientific, technological, and cultural progress than the periods before and after. It would be easier for me to convince myself of this if I could picture some specific things that those medieval peoples could do that would have left the ancient Romans or Greeks scratching their heads. (This may sound to you smarties like a childish way to understand something, but I'm a dumb engineer, and this is just how my brain works.)

As this question is motivated in part by my having gathered that the concept of "dark ages" is now widely considered to be pseudo-historical nonsense, and as my mental image of the dark ages is in Western Europe prior to the 12th-century renaissance, I'd prefer to avoid post-12th-century stuff or stuff going on over in the Byzantine Empire (which I understand was a direct continuation of the Eastern Roman Empire).

I also have noticed that expressions like "A is more advanced than B" can be controversial, so let me define this as meaning specifically "A has the ability, if he wanted to, to do something B could not do even if he wanted to", where that "something" could also include just greater efficiency or whatever.

Today is either December 31st 2014 or January 1st 2015 depending on where you are. Why did we choose this day to be the start of a new day? Why not some other day?

Was seeing prostitutes seen differently while off at war? Would men lie about it? Was it ever brought up? I'm guessing we would only be talking about the rich segment of society (because literacy) but I would be interested to know if there were differences between social classes.

I'm actually interested in this topic among all cultures pre-1600, but I've had more than one question tossed out for being too vague.

When playing a game, we as kids would yell out "Crap!" or "Fuck!" or throw the controller. Were there any such things before video games that made kids so annoyed?

Does anyone know the nature of the original 'letter of the First Voyage' of Christopher Columbus, and which reproduction is the most accurate?

Also, does the 1542 copy of Cabeza de Vaca's 'La Relacion' still exist? For I've seen it mentioned but no one has mentioned where exactly it is.

What regions/countries have diffrent dates as this and does it ever globalize?

I have been increasingly interested in World War 1. The absence of it in my education is amazing to me. I have no idea what it was fought for or how the war was fought or the consequences of the war and how it affected the start of World War II. Can anyone give me (or recommend a resource) for an overview of the war.