The Irish monasteries during this time were the major preservers of learning and literacy in the so-called  Dark Ages.  
Without the Irish monasteries, learning and literacy would have lapsed into oblivion during the Dark Ages.
mnli hypothesis: Without the Irish monasteries, learning and literacy would have lapsed into oblivion during the Dark Ages. premise: The Irish monasteries during this time were the major preservers of learning and literacy in the so-called  Dark Ages.  