Hmmm ... very interesting. obviously Macdonaldus is a Latin translation of Mac Donald - "The son of Donald". Now Donald, and the prefix Mac are both Gaelic - Q-Celtic- and as far as we can tell, the Picts and other occupants of Northern Britain at the time of the Romans spoke Brythonic - p=Celtic - similar to modern Welsh.Now... given that we're told that Macdonaldus was sufficiently well-established to own a farm. Current thinking is that the Gaels from Ireland did not begin wholescale settlement in the far west of Scotland until the 5th century.
This could revolutionise our understanding of Roman period Scotland.
Thanks for this Xguest
Keep up the good work
Cheers
Steven