One may wonder what conditions made it possible for all the countless, able-bodied men, to leave their homes where they were needed the most. Younger brothers not entitled to inheriting the family farm must have made up a large chunk of the warriors.
Viking expeditions are often glorified, simplified and romanticized. However, it is important to remember that the Vikings were responsible of bloody atrocities during their ravages in Europe that can’t be justified ethically or morally – but the times were different back then. One example is the word Geld, later called “Danegeld”. It was a very special form of payment from either a person to avoid losing his head, or have his farm burned down, or from entire cities or nations that paid the Vikings to leave them alone. It’s not pretty and easily comparable to the form of business associated with modern gangsters. That was nevertheless how many powerful men, considered Viking aristocracy, gained their wealth and high status.
In the end the ravages by Vikings differ little from those by any other group of armed warriors before or after them. It just happened to be their time, right there and then, with a number of factors that made them prevail. The Viking Longship was one of the key factors. Envied and feared by all contemporary European realms, this Viking invention enabled them to strike with surprise and lightning speed, and disappear as swiftly, before any slow and lumbering armed forced managed to engage them.
Another important factor could have been their faith and fatalism, where the brave who fell in battle were taken to Valhalla to fight and feast for an eternity. It was a win-win situation so to speak. Either you got rich raiding, or you died raiding and went to paradise. All things must come to an end and so did the Viking Age. Bloody atrocities, plunder and killing on the other hand has continued to this very day, and it is highly unlikely that it will ever stop.