Its authenticity has been questioned (see here), but no one has noticed that the author left signs of his mockery (as well as his knowledge of Hebrew) on page 20:
Yes, either this pamphlet is a joke, or there really was an great Indian peace chief in the early 1790's named Ab Beth Din WyRosh Yeshivo אב בית דין וראש ישיבה -- "Chief of the Court and Head of the Yeshiva."
The speech of Ab Beth Din WyRosh Yeshivo is preceded by one by Gush-Gush-a-gwa, (this joke I don't quite get). Appended is a letter on gardening (!) dated April 3d 1762, and signed by General H. Bouquet (who was a historical personage, though not for peaceful reasons. ).
May the flowers of peace bloom for all nations of the earth --MSK