Which preposition to use with opus

in Occurrences 1%

He saw at a glance that I was conversant with authorities whom he had never consulted, and possessed a knowledge of my subject to which he could hardly aspire, so I gracefully agreed to leave the field to him, and relinquished my magnum opus in its very inception.

on Occurrences 1%

Mr. SHORTER presented the postmaster with an autographed copy of his magnum opus on the BRONTËS.

to Occurrences 1%

And now his followers await the coming of "the Artist Elias," who shall bring the Magnum Opus to its completion.

Which preposition to use with  opus