[Max L]

So getting TK'd like you wouldn't believe in War of the Vikings today made me think, are there any records of accidental "friendly" killing in battle from medieval and ancient times?

That is to say, documentation of warriors mistaking friends for foes in the heat of battle and attacking them.

I have to imagine it would be understandable, especially in conflicts between tribes of the same culture.

[Eric Allen]

I know of one.

Battle of Barnet (1471) during the War of the Roses.

The Earl of Warwick's ally Montague's archers (on the Lancastrian side) mistook the standard of the Earl of Oxford (a star with rays) for the king's banner (a sunburst) when Oxford's men were returning to the battlefield after chasing off a Yorkist detachment and looting the town of Barnet.
It was foggy; they couldn't see well. All they could see was the silhouette of the charge on the banner, not the details and colors. The banner appeared unexpectedly to Montague's rear. They assumed it was Edward IV's reserves. Montague's longbowmen shot.

Oxford's men--wary of the tenuous political dealings amongst the Lancastrians--yelled out they were betrayed. Nearby fellow Lancastrian units heard Oxford's men calling out betrayal and took up the cry, too. The cry quickly spread through the Lancastrian ranks, morale plummeted, and they broke.

So, a "friendly fire" incident on a foggy morning very well may have won the battle for Edward IV and the Yorkists. When the fog lifted, Edward saw Montague and Oxford's men in disarray in the Lancastrian center and took the opportunity to charge. Both Montague and Warwick were killed and their corpses taken to London to be displayed.

[Harry Marinakis]

Those of us who fight can tell you that in the heat of battle, swinging and hacking, sometimes when a friendly steps in front of you they get whacked before you can stop yourself from swinging. I've been on the both receiving end of friendly fire and the delivering end. It's unavoidable.

[Jeffrey Faulk]

It probably happened fairly often, given that there was no real use of uniforms until very recently. There might be some use of heraldic colours, but with common soldiery, not so much. It kind of came down to "if you see someone you don't know, hit them hard".

However I would not be surprised to find that it was recorded far less than the number of actual occurrences, as if the winning side perpetrated it, that would reflect badly upon them. Better to blame the casualties on the 'other side'. Additionally, given the press of the hand-to-hand combat, it would be honestly difficult in some cases to distinguish people killed by their own side from those killed by the enemy, especially if it was just individuals rather than whole units.

[Marik C.S.]

Incidents similar to Barnet, where unclear tactical situations and problems on the field led to troops assuming that other parts of the army had either turned tail or outright betrayed them might be the most common form of "Friendly Fire" on a non-individual level.

The story of the Genoese Crossbowmen at Crecy runs along the same lines for example, the Mercenaries retreated to save themselves from an undesirable tactical position (getting shot from English Archers due to the lack of Pavises&defences on the French side) and were slaughtered by the French Troops who assumed they were about to flee the battle.

I doubt that this would have happened (or at least not as quickly and to a lesser extend) if these were regular troops rather than merely hired hands whose only allegiance allegedly is to coin.
Similarly, if the political situation between Oxford and Montague had been less strained, Montague been more trustworthy - after all he had been a Yorkist before and only recently swapped sides - things might have gone better because Oxford might not have been so keen to suspect treason.

[Mart Shearer]

Friendly fire isn't.

IIRC there are also accounts of English sailors from the south getting driven to shore in the north, where the men of Yorkshire set upon them thinking they were French due to their language.

[Steven Lussenburg]

I think the Battle of Karansebes is the most friendly fire you can wish for.

[Mart Shearer]

Judges Chapter 7:

[Michael Harley]

Was that meant as a joke? or are you really using the Bible as evidence of anything other than late bronze age peasants wishful thinking?

[Mart Shearer]

No joke. I would call it evidence of friendlies killing friendlies in ancient times. You can disagree with the cause if you want, but the results are the same.

[Matthew Amt]

The Bible is as good a historical source as many others. Why wouldn't it be? It has no more "supernatural" element than most other ancient writings, and the Old Testament accounts are actually less biased than most.

Matthew

[Michael Harley]

More ‘evidence’ of death by friendly fire:

[P. Emerson Humphrey]

I ask alternately how common and if it is documented that archers fired too close to the melee line mistakenly. I mean to say cases where missiles aimed intending to hit enemies hit friends in ancient and medieval records. Since the line would be less visible without the high ground even aiming for rear soldiers seems like it could hit friendlies. I liken this to artillery and infantry in later war shelling too close happens so I wondered of this aspect in old times.Thanks for any input. :-)