I'd suggest that Petravore is an anglicisation of the Gaelic "Peadar a' Bhothar" or Peter -of -the -Road. He might well have been a travelling man who happened to have a very good looking daughter who fancied the Cattle Jobber for her husband. (a "jobber" also called a "tangler" was a kind of "in-between trader" who would intervene in a sale, being discussed and argued at a Fair, in order to bring the two parties together to make a deal) Travelling people always frequented fairs in the old days.