Bear in mind every single one of these pretty much is an antiquated weapon, so no guns here.
10) Gladius.
Mass produced steel cutter and stabber, beautifully simple design for killing. Very Roman.
9. Stilletto.
A deadly thin metal spike designed to stab quickly and nothing else. Not a combat blade, but so elegantly and deadly simple. Stab Stab Stab.
8) Shield.
Yes, the shield is a weapon. Shields made Spartan phalanxes and Viking shield walls, but low on the list because onces armour becomes enough protection from most weaponary, the shield is mostly downplayed to parrying only.
7) Quaterstaff.
Thick oak quaterstaff, not the bend of the wax wood staves, but can take sword cuts, hook axes and break limbs, and easily available and easy to train with.
6) Morning star.
It's a lump of spiky metal on a stick whaling around and making contact with skulls, legs, shields, and breaking most of them. It's just a brilliantly simple and brutal weapons.
5) Katana.
Before you fanboys mouth off about how it's so low on this list, there's good reason for it. You can't block with half the blade. The cutting edge of every european sword has to be both for cutting and blocking, the Katana blade has a hard and sharp but very brittle cutting edge. With technique and training this can be accomodated, but as an inherent weapon it's an incredible disadvantage.
4) Spear.
Used by every warrior since the dawn of time, still used in the form of the bayonet. From the Spartan oak and bronze heavy spear to the sarissa of macedonian phalanxes to ash hafted viking spears to 18ft pikes, spears have always been on the battlefied, and for good reason. Pointy stick useful.
3) Longbow.
Training requried - Huge
Output of training - the most deadly ranged army until firearms were readily and accurately available, longbows of about 180lbs draw weight can send arrows far further, faster and more accurately than even most 18th century firearms, it's just the training that meant it was easier to mass equip 500 peasant two months before battle with guns that a lifetime of training for longbowment.
2) Longsword.
Medieval style longsword, designed to be razor sharp and yet heavy enough to provide percussion cuts, can be wielded very effectively one handed or two, and suited to both cutting and thrusting.
1) The Dane Axe.
It's a giant 6ft axe designed to cut through anything, wielded by someone with enough strength to use it effectively, it goes through any armour or horse or shield of the Dark age period. Does exactly what it wants to do perfectly well.