Which preposition to use with unacquainted

with Occurrences 254%

'Can Sir John Ligonier (the commander-in-chief) allow His Majesty to remain unacquainted with the merit of that officer, and can he see such a mark of displeasure without endeavouring to soften or clear the matter up a little?

with Occurrences 104%

"Mr. Ward emphasized particularly the astonishing political ignorance of the German people as a whole, an ignorance quite unintelligible to any one unacquainted with their Press and their political institutions.

Which preposition to use with  unacquainted