Sebastianism

Sebastianism () is a Portuguese messianic myth, based on the belief that King Sebastian of Portugal, who disappeared in the battle of Alcácer Quibir, will return from Morocco to save Portugal. The belief gained momentum after an interpretation by priest António Vieira of Daniel 2 and the Book of Revelation that foreshadowed a Portuguese Fifth Empire. In Brazil the most important manifestation of Sebastianism took place in the context of the Proclamation of the Republic, when movements emerged that defended a return to the monarchy. It is categorised as an example of the King asleep in mountain folk motif, typified by people waiting for a hero to return to save them. The Portuguese author Fernando Pessoa wrote about such a hero in his epic "Mensagem" ("The Message").
Sebastian, the Child King.
King Sebastian of Portugal (January 20, 1554 - August 4, 1578) was the grandson of John III, who became heir to the throne due to the death of his father, João, Crown Prince of Portugal, in 1554 two weeks before his birth, and who succeeded to the throne three years later. This period saw continued Portuguese colonial expansion in Africa, Asia and Brazil. The young King grew up under the guidance of the Jesuits. Luís de Camões dedicated "the Lusiads" to King Sebastian.
The birth of a hero and a myth.
Almost immediately after coming of age, Sebastian began plans for a great crusade against the Moroccans. The Portuguese crossed into Morocco in 1578 and, against the advice of his commanders, Sebastian marched deep inland. At the Ksar El Kebir (Field of the Three Kings) the Portuguese, along with crusaders and several mercenaries from different parts of christiandom, were routed by deposed Moroccan Sultan Abu Abdallah Mohammed II, and after the disastrous defeat against the Saadians of Morocco, Sebastian was almost certainly killed in battle or subsequently executed. But for the Portuguese people, he had just disappeared and would return home one day, to such an extent that, in 1640, King John IV of Portugal had to swear to yield his throne to Sebastian, in case Sebastian (who would have been 86 years old) were to return.
After his death (or disappearance), Portuguese nobility saw its independence gone (1580). In the time of Habsburg rule (1580-1640), impostors claimed to be King Sebastian in 1584, 1585, 1595 and 1598. Because of these events, Sebastian passed into legend as a great Portuguese patriot and hero — the "sleeping king", who would return to help Portugal in its darkest hour.
In 1752, a Sebastianist predicted that a terrible earthquake would destroy Lisbon on All Saints' Day. After the Lisbon earthquake struck on All Saints' Day three years later (November 1, 1755), there was a surge of converts to Sebastianism.
Appearance of Imposter Pretenders.
Since Sebastian's body was never definitively identified after his death, false "Sebastians" arose, claiming to be the former king. The first appeared in 1584; he was a commoner of Alcobaga, quickly apprehended and spared execution by a sentence to work in the galleys. 
A second imposter was a son of a stone-cutter from the Azores, who had retired to a hermitage. Because of his frequent self-inflicted deprivations and penitences, those in nearby communities proclaimed him to be the King, atoning for the misfortune of his subjects. Despite his initial denials, he finally consented to the acclamation of local peasants. Traveling to Lisbon, he was paraded through the streets on an ass, exposed to the jeers of the populace, and publicly hanged. 
A third Sebastian arose in Spain: an Augustinian monk, by the name Miguel dos Santos, who once had been a chaplain of Sebastian and confessor to Dom Antonio, and was ultimately confessor to the nunnery of Madrigal. His appearance recalled the person of Sebastian. In this setting, he met with Gabriel de Spinosa of Toledo, who persuaded him to impersonate Sebastian. He and Spinosa were both captured, forced to confess, and hanged. 
A fourth impostor arose in Naples, but was transferred to a prison in Spain. His claims were undermined by his inability to speak Portuguese.
Late Sebastianism in Brazil.
With the proclamation of Brazil as a Republic in 1889 the Brazilian state became a secular state, in contrast to the former Brazilian Empire, where Catholicism had been the official religion. In imperial administration, the church had very important roles: functioning as registrar for births, deaths, weddings, and even for the recording of property.
The coup d'état against the régime of Emperor Pedro II and the republican reforms brought few changes in most people's lifestyle — for example, universal enfranchisement was not enacted —, the greatest change for Brazilians really was the "godless" government. Catholicism and the monarchy had been closely tied and strongly affected Brazilian people. Most of the opposition movements to the republic in the 1890s, 1900s and early 1910s had religious motivations. The character of D. Sebastião returned to people's imagination: he would come back to defend the divine right of the Brazilian Monarchy, who were directly descended from the Portuguese monarchs, to rule in Brazil and to defend Catholicism, which had been removed from government by the Republic.
In the state of Maranhão, there is a belief, especially on the Lençóis Island, on the coast of the state, that King D. Sebastião would live on this island, having many legends around his figure, how to become an enchanted black bull with a star on the forehead. The leather of the bull of Bumba-meu-Boi, especially those of sotaques of zabumba e pandeiros of costa de mão, from the regions of Cururupu and Guimarães, usually have the tip of the horns in gold metal and, embroidered on the forehead, of gold and jewels, in allusion to the legend. Afrobrazilians religions in the state, like the Tambor de Mina and the terecô, also has special relation with the king Sebastião, that figures like an encantado (an entity).