Help Appreciated

Hi everyone,

I'm not sure if this is the right forum on which to post, but here goes...

I was thinking about the fact that I have 2 parents, 4 grandparents, 8 great grandparents, and so on...

I am of Greek heritage, and I thought back to the time of my ancestors in Ancient Greece.

Now, I'm going to make a few whopper assumptions here...

Ancient Greece started in about 800BC (say, 2,800 years ago for rough figures)

The population of Ancient Greece was around 1,000,000 then.

A generation reproduces itself every 25 years (give or take)

2800/25 = 112

So there have been 112 generations from the "beginning" of Ancient Greece until now.

Now, 2 to the power of 112 = 5,192,296,858,534,827,628,530,496,329,220,096 whatever that number is...

So there must have been THAT many of my ancestors all walking around at the same time in 800BC. But I know that's impossible, because that's more then the population of the world, even right now.

So, I know my mathematics is wrong, but where?

I'd appreciate some feedback.

BB