Tércio, Daniel. A Vocaçã do Círculo
Title trans.: The Circles' Vocation
Summary: A man from the Lisbon of our world is transported to the "Olisipo" of another in which magic works. There he falls in love with a witch and must aid her in saving her kidnaped grandfather, who has been carried away to yet another Olisipo, seemingly still mired at an Roman-era technological level.
Published: Caminho 1984.
Original in: Portuguese.