Which preposition to use with viceregent

of Occurrences 2%

Hugh de Payens, before his departure, placed a Knight Templar at the head of the order in England, who was called the prior of the temple and was the procurator and viceregent of the master.

over Occurrences 1%

Bellizarius be Viceregent over all Those conquerd parts of Affrick we call ours; Hubert the Master of my Henricks Horse And President of what the Goths possesse.

Which preposition to use with  viceregent