Which preposition to use with sanctorum

of Occurrences 9%

Such indeed is the infatuation and credulity of the ignorant that, we are confidently assured, a notorious German quack had within one year so many half-guinea applications that he netted £2000; and that the glass bottles in which the precious nostrums were conveyed from the sanctum sanctorum of the mendacious empiric in high Germany, who made his debut in this country by hawking about Dutch drops, amounted to as many two-pences.

Which preposition to use with  sanctorum