Which preposition to use with slidell

of Occurrences 2%

At the same time, Judge Slidell of Louisiana was appointed as the representative to France.

at Occurrences 1%

The resolution calls for the "instructions and orders issued to Mr. Slidell at any time prior or subsequent to his departure for Mexico as minister plenipotentiary of the United States to that Republic."

Which preposition to use with  slidell