Which preposition to use with welched

of Occurrences 1%

He cursed the man Charles Stuart, and every councillor by name; he cursed the Persecutors, from his Highness of York down to one Welch of Borrowstoneness, who had been the means of his first imprisonment; he cursed the indulged and tolerated ministers; and he cursed every man of the hill-folk whose name he could remember.

on Occurrences 1%

Offhand, I'd say you were simply trying to welch on a fair bargain.

Which preposition to use with  welched