D. João de Castro (1550-1628) : como um resistente se tornou profeta
Everything indicates that D. João de Castro was the first one to establish the basis for myth of D. Sebastião. Disenchanted with D. António and his pretensions to the throne of Portugal in the year of l580, D. João made use of a vast collection of old and new prophecis to support the belief in the return of King D. Sebastião, who disappeared at the Battle of Alcácer-Quibir. With this he discredited D. António 's aspirations but also rejected the Castilian pretensions to the Portuguese throne. It is interesting to notice that what started as a simple political strategy soon became a strong faith in the myth of D. Sebastião 's return. Like in many other similar situations. prophecies tend to be used for propagandist purposes: they became the basis for a "Sebastian ideology", which turn out to be a strong fundament for the resistance cause.