One term used throughout the years of the Viking settlements in Britannia was the Danegeld. This meant any payment made to the Danes (or any other Norsemen, for that matter) for NOT attacking, pillaging, or doing any other sort of bad things. We might call this blackmail today, but it was an accepted practice back then. Many things they did back then are not accepted practice today, but those were different times.
Anyway, let’s examine the word Danegeld. The first part of the word has an obvious origin: Dane. The second part of the word would seem to mean “payment,” as in, “That’s the money that we pay the Danes to stay away from our farms, women, and children.” A similar term can be found in wergild, the old Saxon term that has come to mean “blood money”: This was money that one Saxon family would be required to pay another family for killing that family’s warrior. Although it is tempting here to say that geld and gild are the same suffix, this cannot be convincingly proved. The suffix gild, tacked onto the end of wer, as in wergild, was in use long before the Danes arrived and began getting their geld. It could very well be that Danegeld is a term introduced into Britannia by the Danes themselves. Nonetheless, the contention that geld and gild are the same because they both mean “money” is correct insofar as the cause goes.
So why did the “Danes,” as they were groupingly called by the Saxons, tire of this geld and keep on attacking? Well, it wasn’t as simple as all that. That question presumes that the Danes, Vikings, Northmen, or whatever you like to call them were one large fighting band (or settling band), acting under one common authority for one giant, overriding cause. Nothing could be further from the truth. As with the Saxons when they arrived, the Northmen were, more or less, bands of brothers (or whatever else kinds of family members), looking for booty, brides, and farmland, usually in that particular order. That they found the land to their liking and decided to stay is more a compliment to the land than it is to the invaders. Some Northmen were satisfied with the spoils of their invasion; others were not. These latter are the ones were causing all the fuss, and it was these latter that Alfred and others before him and since had to deal with in order to keep order among Saxon England.
The Danegeld was one way to keep order. Saxon coins never seemed to run out for a few years, but then times got tough. Given the choice between feeding his family and paying a foreign neighbor not to raid his crops, a farmer might very well think long and hard before choosing but usually put his family first. This caused all kinds of trouble; because a Dane who didn’t get his geld peacefully usually determined to get it by force. Thus did the conflict escalate and thus into the breach did step Alfred.