The wedge formation was for...?

[Black-knight-blues]

aye, them vikings knew what they were doing!

[Black-knight-blues]

they also befriended bysants and started to work for the emperor as his personally bodyguard.
the natives thought they were rather loud...
 

[Black-knight-blues]

yes, booze was a must!
and let us not forget all the battles for the Raven-banner!
wonder what the banner's last master did with it....

[Archonsod]

An infantry unit advancing in line shoulder to shoulder is imo a more defensive formation as it means that fewer men will actually do the fighting,

Hows that? You'll be using an increased frontage, plus the ranks behind are able to push the formation forwards once engaged.

but you are more suited to facing cavalry and flanking manouvers by infantry and skirmishers..

Not really. Against cavalry you need a good solid spear (or similar weapon) wall facing the cavalry. Skirmishers should be met by your own, or driven off with cavalry. There's no really good infantry formation for dealing with them.

The wedge is imo far more offensive it isnt really any effective if the enemy have cavalry

Most formations are, but the advantage of the wedge is that enemy cavalry shouldn't be able to reach you, without ploughing through whichever unit you've engaged.

in a pitched battle it is to easily surrounded to,

That's the point. You want the enemy to end up on either side of the wedge, where you have a long frontage on both sides.

[Cirdan]

Alexander the Great's Macedonian cavalry are also supposed to have used wedge formations when charging the enemy.

Indeed. Alexander is credited with inventing the 'proper' wedge, by shaving off the 'useless' half of the Thessalian diamond formation.

[Amman de Stazia]

The vikings didn't meet peasant levies. The vikings were peasant levies.

The reason why the vikings could do the sort of damage that they did in Europe, was that they had the numbers. The Norse population was nowhere near the one in England or mainland Europe, but because every free man was expected to own a spear and a shield, enormous armies could be amassed in far less time than in feudal kingdoms, where a core of trained men bore arms, and others didn't.

So if there were armies meeting the vikings, they were very often trained armies, far inferior in numbers.

? really?

I would have thought more likely that:

1)  The norse who were the equivalent of the levy simply stayed at home, so those who did go viking or invading were men who wanted and expected to fight, and had equipped themselves accordingly with bloodlust, helmet, sword and shield.

2)  They would have been outnumbered by the defenders, nett, but the norse force would have been one hundred per cent warriors, whereas the defenders might have been one-quarter warriors, and three quarters levy.   

3)  The warriors would be better trained than the norse, and the motivation of defending their homes would balance the bloodlust of the norse, but they would be outnumbered, and reliant on the levy to prevent force of numbers destroying them.

[Black-knight-blues]

the norse were acutally fairly well trained. For in the winter time, there was little to do, so they spent the days by doing minor work and train for battle.

[Cirdan]

Actually, the feudal system was far from fully developed in the 9th century; moreover, large cities such as Paris were never under feudal rule, and their defenders would have been militias supported by whomever could bear arms, although in the 9th century urban militias were far from the effectiveness they would achieve later on. In the case of the Frankish kingdoms, their vulnerability to raiding came from weak leadership and internecine strife, rather than a structural weakness.