There is a clip is this video taken from the movie "O Quinto Império" / "The Fifth Empire", a movie by Portuguese director , Manoel de Oliveira depicting Dom Sebastião and the tragedy of Alcacer Kibir..The concept of this fifth empire is interwoven with portuguese history ,it was not a territorial empire , it was a belief, a spiritual and linguistic force that would spread throughout the whole world. It had to do with the age of discovery and the portuguese expansion, but after the disastrous defeat in Alcacer Kibir, the death of the king and the loss of independence , it seemed that that dream was gone for good.
It was Father António Vieira( one of the greatest portuguese writers ever, that presented King John IV , the king that lead the process of restoration of independence in 1640, as a saviour that would restore the grandiosity of Portugal and establish "the fifth empire" that would suceed the previous empires before Portugal´s Golden Age . As Portugal´s Golden Age and Empire crumbled , the idea of the fifth empire became even more mythical. Camões´s epic poem , "The Lusiads" became the portuguese literature masterpiece and Fernando Pessoa wrote "Mensagem " / "The Message" in the 20th century, where he summons portuguese conscience and recalls portuguese history conveying the idea that Portugal as a nation must fulfill it´s destiny that is :build the fifth empire" led by the "hidden one" and unite the world pollitically, culturally and spiritually.
Note : I found it interesting to explain the concept of " fifth empire " because it happens it´s still a myth and a belief in nowadays Portugal.That means that there is deep belief that it will happen in the future because there are prophecies in portuguese literature " Trovas do Bandarra " that state that it will.

REALLY REALLY GREAT VIDEO. Just one thing. After Sebastian I death; his uncle; Henry I “the cardinal” (John’s III brother) became King. He couldn’t have legitimate children either getting married (and The Pope didn’t let him because of Philip II orders). So when he died (in a couple of years) it’s when Philip II became King of Portugal.

Would you like more videos about this topic with other houses/countries?

Couldn´t help it. I just had to comment on this one.
This "inbreeding " was a kind of political plan to make a joint royal house that would rule Iberia.Portugal went along with the plan after king Manuel got to the throne when the kingdom became rich beyond belief with the spice trade .( Before, the kingdom avoided marriages with spanish princesses, usually Aviz princes and princesses married among each other to prevent dangerous situations like the one that brought the Burgundian dynasty to an end). king Manuel wanted to play the main role in the process, certainly ignoring that Spain wanted to play the main part too.
The process ended with Filipe II / I of Portugal getting the portuguese throne after his nephew , Dom Sebastião , died in the battle of Alcacér Quibir, leaving no heirs.Portuguese historians point out that Filipe said when he got Portugal: " I inherited, I bought it and I conquered it". Filipe I is considered to be a good and kind king to the portuguese. In fact he kept all the promises he made when he was crowned king of Portugal.( Portugal was to remain an independant kingdom , but it had the same king as the neighbouring spain)
However his followers soon forgot those promises and the fact that Olivares had convinced Filipe IV/ III to make Portugal a province of Spain , caused the portuguese nobility to revolt.
It ´s really Interesting to notice that both kingdoms/countries had a similar trajectory but sometimes great rivalry in the development of each country´s history.
P.S : Thank you for your videos. They are very interesting.

Their greatest foe they couldn't conquer.