After looking at a number of Title pages, I found

jussu senatus
By order of the Senate.

on works published collectively such as statutes,books of medical recipes,public lectures. And one example which almost fits

iussu senatus, iure iurando pollicitans,
by order of the Senate, promising on oath

These are J not I, and in abbreviations Jus, Jussus are the most frequent Js. However in this case the 'Senatus' is Genitive, 'of;' and so it is not the Senate 'pollicitans,' making promises.

After looking at a number of Title pages, I found

jussu senatus
By order of the Senate.

on works published collectively such as statutes,books of medical recipes,public lectures. And one historical example which almost fits

iussu senatus, iure iurando pollicitans,
by order of the Senate, promising on oath

These are J not I, and in abbreviations Jus, Jussus are the most frequent Js. However in this case the 'Senatus' is Genitive, 'of;' and so it is not the Senate 'pollicitans,' making promises.