Affirmanti, non neganti, incumbit probatio: The proof is incumbent on the one who affirms, not on the one who denies.
Affirmantis est probare: The person who affirms must prove.
Printed copy · Anthology Volume 5, page 623Printed copy from The Tender For Law Anthology, Volume 5, page 623 (printed 13 June 2014). Added by this site; not part of the Facebook export.