Egidio da Viterbo (1469–1532) wrote his Book on Hebrew Letters (Libellus de litteris hebraicis) in 1517 to persuade Pope Leo X to reform the Roman alphabet. Behind this concrete, if farfetched, proposal was a millenarian theology that Egidio revealed by introducing his Christian readers to Kabbalah, whose first Christian advocate, Giovanni Pico della Mirandola, had done his pioneering work only a few decades before. Inspired by Pico and by Johann Reuchlin, Egidio also absorbed the Platonism of Marsilio Ficino, applying it in the Libellus to a Kabbalist analysis of the Aeneid, which he reads as a prophecy of papal victory over the Jews at the end of time, while also seeing Pope Leo as a modern-day Etruscan. But the main source of Egidio’s apocalyptic theology is a medieval Hebrew book, the Sefer ha-Temunah, which in Italy was new to Jews at the time Egidio read it.