Which preposition to use with garreteer

in Occurrences 1%

Flecknoeblunderingly classed among the Laureates by the compiler of "Cibber's Lives of the Poets"was an Irish priest, who had cast his cassock, or, as he euphuistically expressed it, "laid aside the mechanic part of priesthood," in order to fulfil the loftier mission of literary garreteer in London.

Which preposition to use with  garreteer