Well, until the invention of plate armour, most swords were used with one hand, with a shield as the other hand
hmm...hand a half sword/bastard sword and some earlier greatsword appear far much earlier before plate armor take in place on battlefield particulary the Oakeshott type XIII and XIV. The tip of the blade do become narrower to suit the need of its piercing capability in later period (at least after 1366)
A single arrow which penetrates is comparable to a single blow of a melee weapon, but the chance of being repeatedly penetrated by an arrow is unlikely.
Arrows mostly cause their damage from either bleeding, or the lucky penetration to a major organ (VERY unlikely if it goes through even a bog-standard gamberson and chain armour, yet alone plate)
Infection is a nasty thing which caused many deaths by arrows, but its way too slow to be reliable in a fight.
A dude with 5 arrows partially stuck into him can potentially still fight and charge ahead, a dude with 5 mace blows is probably wondering where some of his bones went.
Poison arrows/Dirty arrows were used, but I don't really see any statistics that it was particularly common, normally dirty weapons were frowned upon in medieval warfare (like bloody swords and such).
an arrow is a large sharp object and, unlike a gunshot wound such as from low velo musket, continued abrasion from inside the wound can and will further aggravate the wound that it made. An arrow stuck and basically Any movement on your part that involves the area around the arrow wound will bring more pain and possibly cut you more. And if the arrow hit you anywhere besides the butt or maybe the back, then it's going to be a major problem fighting with it. The protrusion is a significant obstacle to any kind of effective swinging, stabbing, running, riding, etc.
Most arrow were aimed at torso, sometime a soldier would get hit in his arm or leg but like i said above it would become a hindrance to his fighting capability. The bad thing, Torso is home to major vital organ of the body. either your lung or your abdomen. Unlike sword or mace, an archer could do this from distance.
A sharpened longpoint bodkin arrow could even penetrate the best gambeson and some earlier unriveted mail
Here is a sheet on how Medieval armors stacked up against Halberd blades, lances and arrows(the ammount of energy needed to penetrate them) from
Knight and Blast Furnace by Alan Williams.(Keep in mind Roman mail was heavier and had smaller links than Medieval mail)
On 1.9mm Wrought Iron munitions Plate armor(about the same thickness of Lorica Segmentata when not overlapped)(without padding btw)
>190 J from Blade
>100 J from Lance
>75/80 joules from an arrow
Mild-Steel Mail with Linen padding(16 layers)
>200 J from blade
>200 J from lance
-80 J from arrow pierced the mail, 100 J ripped through the padding completley.
Low carbon steel Mail with Linen padding(16 layers)
-170 J from blade
-140 J from lance
-Arrow result was same as Mild steel.
Linen Jack of 16 layers
-80 J from blade
-50 J from lance
In the mail test 80 J arrow pierced the mail+Linen. It only took 20 more J to rip though the 16 layers of Linen completley. Buff leather(hide) was no better against arrows since it only to a 30 J arrows got through.
Poison arrows/Dirty arrows were used, but I don't really see any statistics that it was particularly common, normally dirty weapons were frowned upon in medieval warfare (like bloody swords and such)
There is a Byzantine source describing the Slavs as making use of poisoned arrows.
The Dacians (and even the medieval Moldovans) commonly employed poisoned arrows against their enemies. Maurikios also stated that the Slavs and Antes used poisoned arrows. The poison was drawn from the poisonous venom of vipers that live in the Carpathian mountains.
Another Byzantine source suggesting the use of poisoned arrows is Leo VI's Taktika. From Osprey's "Romano-Byzantine Armies 4th-9th Centuries
"Leo VI's Taktika advised Byzantine archers to use poisoned arrows against the Muslims' horses, a tactic which may have been adopted from the Slavs."
The african archer from mali empire and nubian kingdom also known to employ poisoned arrow and javelin. The mali archer for example, inflicted a series of defeats against the Portuguese at when they defended against the raid on the Senegambian coast in 1444. Nubian archer famously defeat arab fast cavalry with the help of poisoned arrow and superior marksmanship