The history of Jews in Iquitos, dating from the late-19th-century rubber boom that transformed this far-flung Amazonian outpost into a once thriving city of imported Italian marble and a theater designed by Gustave Eiffel, was almost forgotten. But Mr. Reátegui Levy and a handful of others began organizing the descendants of dozens of Jews from places as varied as Morocco, Gibraltar, Malta, England and France who had settled here and deeper in the jungle, opening trading houses and following their star in search of riches and adventure.