After the defeat at Alcácer Quibir, many efforts were made to ransom imprisoned Portuguese soldiers in Morocco. Several soldiers returned to Portugal, which led many Portuguese to believe Sebastian had survived the battle and would return to claim his throne. This led to Sebastianism, the belief that Sebastian could return at any moment. Politically, there was a belief that Philip was not the rightful heir to the throne. Subsequently, imposter pretenders appeared in Portugal who fraudulently claimed to be the king. During the time of the Iberian Union, between 1580 and 1640, four different pretenders claimed to be the returned King Sebastian. The last of these pretenders, who was in fact an Italian, was hanged in 1619, while another was obtained by the Spanish from Venice, tried, found guilty and hanged in 1603.