More than 400 years ago, an explorer pleaded with the King of Spain to fund a daring expedition to a land he said he had discovered in the Pacific.

Pedro Fernandes de Queirós said the great southern land he had found was full of spices, nutmeg and cinnamon.

The explorer wrote time and again to the king seeking help to return, but died before he could sail back into the Pacific.

The State Library of New South Wales has unveiled two new documents that add to its collection showing how close we came to having siestas and sangria as a way of life.

"We could have been Spanish, with Spanish cuisine and Spanish language," state librarian Alex Byrne said.

There have been past claims that Queirós was the first European to land on Australian shores around 1605, but it is generally believed his ship in fact mistook a large island that is part of modern-day Vanuatu, nearly 2,000km further east, for the fabled great southern land.

Queirós named the discovery Austrialia del Espiritu Santo (the Southern Land of the Holy Spirit), before sailing back to Mexico.

The Portuguese-born explorer then returned to Madrid in 1607 and began petitioning King Philip III of Spain.

The petitions formally requesting sponsorship were known at the time as "memorials".

The State Library has obtained all 13 that are still known to exist.

The library put two of those memorials on show for the first time on Thursday, having recently acquired from private ownership for $865,000.

It is believed Queirós had 14 of the memorials produced, but the first of them is yet to be discovered.

A land of 'fine strapping people'

State Library of NSW boss Alex Byrne (left) and NSW Arts Minister George Souris unveil the two Pedro Fernandes de Queirós memorials recently acquired for the library's collection. ( State Library of NSW )

Dr Byrne says Queirós did not hold back in trying to convince the King to bankroll another voyage.

"He gilded the lily. He said it's got all these wonderful spices, nutmeg and cinnamon, it has timber to build vessels for your majesty's ships, it has people there, fine strapping people that we can Christianise and we can do that before the Protestants get there," he said.

But a journey to the other side of the world in the early 17th century had to overcome many frightening fables.

"They knew less about it than we know when we send a space shuttle off towards Mars or even further," Dr Byrne said.

"They imagined there were monsters there, so he was trying to persuade the King to put his money into a very perilous adventure."

Queirós became increasingly frustrated as King Philip III ignored his requests.

"As time went on and the king didn't respond to his submissions, he became more and more shrill, importunate, trying to persuade the king to do it," Dr Byrne said.

While the Spanish King remained unimpressed, news of the discovery eventually spread.

"The documents were highly confidential, just like Cabinet submissions today, so when one leaked out the spies would have heard about it and then the rivalry increased," Dr Byrne said.

"After that we had the Dutch along the (Australian) west coast."

In a tragic twist of fate, King Philip III finally agreed to fund another expedition, but Queirós died in Panama before he could again set sail on the Pacific.

"It could have been quite a different world couldn't it? And who knows where it would have gone, but I guess they're the quirks of history," Dr Byrne said.

The new acquisitions will be on special display at the library until February next year.