'Gypsies Tramps and Thieves' as the song has it.
Skellig Michael is a case in point. In fact a very pointy rock in the Atlantic making it very difficult for the faithful to come and pay their Peter's Pence but home to monks nevertheless.

Monks inhabited it at some point between the sixth and eighth centuries. Apparently there were never more than twelve monks and an abbot living on it at any one time. They created their own water gathering and purification system as well as creating kitchen gardens to grow food.
It was important as the supposed burial place of Ir son of Mil of Spain. The founders of the Milesian dynasty in Ireland.
There was also a hermitage.
And a report of an attack by Vikings in 823. Why would Vikings attack a place like that. I know they liked doing that sort of thing, it went with the job description but I doubt whether Skellig Michael was a Lindisfarne or Iona. Unless they needed fresh vegetables.
According to wiki they moved out in the twelfth to thirteenth centuries because of climate change or possibly a change in
changes to the structure of the Irish Church
which I think is more probable. That period seems to be a changing point for many things.
And then much later the place becomes a lighthouse.
Skellig Michael remained in the possession of the Catholic Canons Regular until the dissolution of the Ballinskelligs abbey during the Protestant Reformation by Elizabeth I in 1578.[2][6] Ownership was then passed to the Butler family with whom it stayed until the early 1820s, when the Corporation for Preserving and Improving the Port of Dublin (the predecessor to the Commissioners of Irish Lights) purchased the island from John Butler of Waterville in a compulsory purchase order.[3][6] The Corporation constructed two lighthouses on the Atlantic side of the island, and associated living quarters, all of which was completed by 182
https://en.wikipedia.org/wiki/Skellig_MichaelThe island is also called the Great Skellig or in Irish Sceilig Mhór. In Scots and northern English 'mickel' and 'muckel' mean great. I don't want to deny the Irish anything but could Michael be an insular term for big or great?
It was important enough to have been included on Italian and Spanish portolan charts. Oh, and apparently they could perform miracles with a never ending supply of wine.
http://www.worldheritageireland.ie/skel ... ackground/The etymology of Skellig is rather interesting. It is described in the sites I've seen as meaning a splinter of rock or something similar. Which it is certainly. But an online Irish dictionary goes further. Under the entry for 'scillig' we are told that as well as meaning a 'shell' or 'husk' or 'flake' it also refers to speech. Which could be a reference to the sermons and prayers of the monks. With the interesting extra of 'spouting lies'.
3. Prate, prattle. Bheith ag ~eadh (cainte), to talk incessantly. Ag ~eadh éithigh, spouting lies
http://www.teanglann.ie/en/fgb/scilligSo there we have it, monks, hermits and lighthouse keepers with the added bonus of Vikings. I think it's got a connection with the Michael Line as well hasn't it?