The Battle of Alcacer Quibir took place on August 4, 1578 by Alcazarquivir in Morrocco between the Portuguese army and the troops of the Moorish Sultan.

The battle had been King Sebastião of Portugal's dream since he was a child. He wanted to fight the Moorish people and submit them to Christianity.

The Portuguese army was small, due to problems the colonialist country was facing. Legend says that young King Sebastião promised to his men that the cross would win against the crescent and that they didn't need to fight: he could kill every Moor on Earth by himself. It didn't happen. The soldiers ran away from the African Plaza , and after a couple of hours, they came back to Alcacer Quibir. Neither their king nor the Moors were there.

During the Spanish dominion over Portugal, many people taught that the 18-year old monarch was still alive, perhaps taken prisoner by the Moors. They hoped that he would come back to his homeland and claim the Portuguese throne once again. The believers in this theory where called "Sebastianists". Many people, willing to conquer the Portuguese throne, claimed to be King Sebastião. All of them were impostors. The last one of them, an Italian, was killed in the 1630s.