The 16th-century artifact was bought by Channel 7 chairman and art collector Kerry Stokes and is to be made available to the public for the first time in 500 years.
Also known as a Book of Hours, the illustrated manuscript featured intricate paintings by the best Renaissance artists of its time, but relatively little is known about it.
Mr Stokes revealed in an interview on Sunday Night he was excited to add the tome to his collection, but not for religious reasons.
"I have a reverence with this book because of what it is and what it stood for and this was a moment in time when the church and civilisation was changing. This was a moment in time when we were just starting to discover that the world was round," he told reporter Steve Pennells.
"This is so unique I expect a lot of people will want to come and see it — we will have something else to offer that nobody else has and that’s the Rothschild Prayerbook."
Australian art scholar Dr Kate Challis is one of few people alive today who have examined the book.
Australian art scholar Dr Kate Challis
“It was brought to me and I held it in my hands and I had goose bumps at one moment because I thought, 'Oh my gosh I am holding this book' and there are people who lived 500 years ago who held the book exactly the same way as I did including probably Hitler himself," Dr Challice said.
Lost for over 300 years, it earned its modern name after surfacing in the private collection of the world's most famous banking family, the Rothschilds.
It was stolen from the family by Adolf Hitler during WWII and the Rothschilds spent 60 years fighting the Austrian government for its return.
Experts suspect the book was made for international clientele and members of the Habsburg court in the Netherlands.
The pages are made from animal skin and the borders painted with gold leaf but, mysteriously, four pages are missing.
“It must have been commissioned for an important member of the court and this is the intriguing thing about it, we don’t really know who it was made for," Renaissance manuscript expert Eugenio Donadoni said.
Mr Stokes has announced that the Rothschild Prayerbook will go on tour next year, with public exhibitions planned for Canberra and Melbourne.