What is the origin of perorate?

The verb perorate, “to speak at length; make a long, grandiloquent speech,” comes from Latin perōrātus, the past participle of perōrāre “to plead, harangue, argue a case to the end; deliver the final part of a speech, wind up a case.” Perōrāre is a compound of the preposition and intensive prefix per, per– “through, thoroughly” and the simple verb ōrāre “to beseech, supplicate; speak before a court, plead.” Perōrāre and its derivative noun perōrātiō (inflectional stem perōrātiōn– “peroration”) in Latin imply grandiloquence and forcefulness, but not length, let alone long-windedness, which is a connotation that has always existed in English. Perorate entered English in the early 17th century.