Student or Learner
In sooth, the year in question had been very propitious to the immigrants; who, flocking in from eastern settlements in goodly numbers, were allowed to domiciliate themselves in their new homes, with but few exceptions, entirely unmolested by the savage foe. So much in fact was this the case, that instead of taking up their residence in a fort--or station, as they were more generally called--the new comers erected cabins for themselves, at such points as they considered most agreeable; gradually venturing further and further from the strongholds, until some of them became too distant to look hopefully for succor in cases of extreme necessity.
--- I don't understand the bolded part of the sentence. How to rephrase it?
I am not a teacher.
"So much in fact was this the case" here refers to the immigrants who were unmolested by the savages. They were "unmolested" to such a great amount that they started building houses for themselves farther and farther from the security of the fort.
In other words, if the "savages" had attacked often, the immigrants would have stayed closer.