Reddit reviews Weapon: A Visual History of Arms and Armor

Since you are looking for some reference books, here are some that I resort to using quite often in my world-building process.

Guns, Germs, and Steel: The Fates of Human Societies by Jared M. Diamond

Plagues and Peoples by William H. McNeill

Weapon: A Visual History of Arms and Armor by Roger Ford

What People Wore When: A Complete Illustrated History of Costume from Ancient Times to the Nineteenth Century for Every Level of Society by Melissa Leventon

The History of Money by Jack Weatherford

If you need more, I can list more. I have a reference book for just about anything you could imagine in my ever-growing personal library.

Remember seeing this in an excellent visual encyclopaedia I checked out from the library as a kid in the mid 90's.

Fairly certain it was Weapon: A Visual History Of Arms And Armour if it wasn't Warrior: A Visual History Of The Fighting Man

Well a large difference would likely to be in the material and workmanship of the weapons. Roman swords were produced of relatively high-quality steel in large facilities known as fabricae who's sole purpose was to produce weapons and equipment for the legions (I'm guessing from your tag you know this, but I'm extrapolating for others that may come along and read).

On the other hand, Anglo-Saxon weapons were mostly made of iron and low-quality steel produced in local forces and smithed by local craftsmen, except in rare cases where higher quality steel was traded for. This would have made the Roman weapons harder, more rugged, and able to take and keep a better edge for longer. A roman's sword was expected to last him (with repairs and maintenance) his entire campaign (indeed, his pay would be docked if he required a replacement). As anyone who's used a iron or cheap steel weapon for any period of time can tell you, they frequently will be bent, chipped and lack an edge by the end of even a couple hours and require extensive resharpening or even reworking. I don't feel comfortable speculating on exactly how long an Anglo-Saxon would keep to one particular weapon, but it's safe to assume that they were not viewed with the same aire of longevity that roman swords were.

I recommend this book for further reading. It's one of my favorites.

Weapon: A Visual History of Arms and Armor was very popular when I was in school. Everyone loved looking at the weapons and reading about them. I can't remember how easy the readings were, but it would definitely interest him!