The selected texts present prophetic writings written by D. João de Castro of Portugal (c.1550–c.1628). Regarded as the “inventor” of Sebastianism, he was the most prominent defender of the return of King D. Sebastião (1554–1578) to Portugal, after the Alcácer Quibir battle in August of 1578. Defeated by the Muslims in North Africa, D. Sebastião was considered dead and succeeded by Cardinal-King D. Henrique (1512–1580). Between 1578 and 1580 several candidates to the throne emerged to be vanquished by Felipe II of Spain (1527–1598). D. João de Castro took part in the succession dispute of Portugal—he first stood side by side with an opponent of the ambitions of Felipe II, D. Antônio (1531–1595), Prior of Crato, with whom, however, he quickly disagreed. From the late 1580s onwards, he began writing about the possibility of D. Sebastian being alive and returning to rescue the kingdom of Portugal from the Spaniards. The selected writings present D. João de Castro’s transition from politics to prophecy, deeply influenced by his performance within the group involved in the defence of the false D. Sebastião who appeared in Venice (1598).