Peter - I think you will actually enjoy this video. Its probably the BEST history ive found, without it being a 12 hour university course.

http://video.pbs.org/video/1051895565

Yamah - Archeology can prove many things, yet open up a plethora of other questions. Lets use your example of the arrowhead (good common example)

The first thing they would do is try to identify the age. This can be done a few ways. Carbon dating, in combination of how deep he was buried, what he was buried with, and pottery shards.

The second thing to do, is to determine the cause of death. IF there is no trauma, then they have to say that the arrowhead was something they added to the burial (like we put flowers ont he grave today)

They can see if there was any warefare, due to the skeletons lack of/apperance of trama, as well as other archeological evidence in the surounding area. IF there isnt other tools of war around in the same strata, then theyd have to assume he died of a natural death or even possibly poisoning (they can still tell that through chemestry)

They can aslo tell how old the skelleton was, and if it was male of female.

Now that you have the age and the area, you can find out exactly what civ its from. From there you can look up texts from that area, and others who have had contact with them, to see if there actually was a battle, see if there was sacrifices being practiced.

You have to remember, medical texts from the ancient world surivive, so we can use those to prove how he died.

BTW, everything is theory, even religions, because alot of the pagan traditions they are based off of, used a sort of scientific method, told by using alligories. Some are just more proven and accepted then others.

ANd once again, I paraphrased so i dont write a gigantic wall of text so its easier for people to read. All I said isnt as much speculation , as it is corrobarated with archeological evidence...

And yes, lots of that evidence proves some of the events in religios tecxts, because they were written during real events and times in real places by real people.