Roger Crowley

John I, the king of Portugal at the end of the 14th century,

There was an Anglo-Portuguese alliance.

He was married to Philip of Lancaster, who was the daughter of John of Gaunt.

And that introduced into the mindset of the Portuguese royal family.

I mean, the children of this alliance were cousins of Henry V, and therefore they were

kind of inspired by this parallel idea of doing great deeds, of doing wonderful things.

So part of this Anglo-Portuguese alliance conjured up a spirit of adventure of noble and heraldic deeds that created a climate in which they were going to

spring out beyond Portugal into a new world.

It was cast somewhat as a crusade because they knew that there were Muslims in North Africa and on the African coast.

So it was sort of like an Arthurian court, if you like.

It wasn't quite the same as a merchant culture, which was going there to get goods.

These were a culture of doing great deeds, doing heroic things.

Yeah, absolutely.

And they developed the sailing technology quite quickly, actually.

And they slowly worked out how the winds worked effectively.

You could sail down the coast of Africa, but you found it very difficult to come back.

And over a period of time, they realized that you actually had to swing out into the Atlantic, pick up a wind to come back again.

And over a period of 30, 40, 50 years, they worked out how the Atlantic winds worked.

The son of John I...

was an extremely clever guy.