SIX religious paintings believed to have once been destined for the New World but never delivered, have finally set off on their transatlantic journey 370 years late.

Joseph, Naphtali, Asher, Dan, Levi and Reuben, have hung alongside their father Jacob and six other brothers in the Long Dining Room of Auckland Castle, in Bishop Auckland, for 260 years.

But now the life-size portraits created by the Spanish Golden Age master Francisco de Zurbarán in the 1640s, are taking an 18-month break to the United States – the first time they have been shown outside Europe.

The works were bought by Bishop Richard Trevor in 1756.

Their 5,000 mile journey stateside, where the paintings will be exhibited at both The Meadows Museum in Dallas, Texas, and The Frick Collection, in New York, marks the start of the multi-million pound restoration of Auckland Castle and the many significant works it houses.

While in the United States, the paintings will be the focus of an in-depth technical and art historical study supported by The Meadows Foundation and The Frick Collection, at the Kimbell Art Museum in Fort Worth, Texas.

Infrared reflectography, ultra-violet light, X-radiography and pigment analysis, will be used to unlock the history of the works’ artistic creation.

The findings will then be made publicly available at the United States exhibitions, as well as Auckland Castle from May 2018, when Jacob and his 12 Sons will once again hang together at the former palace of England’s only Prince Bishops.

Clare Baron, Auckland Castle’s temporary exhibitions curator, said: “Jacob and his 12 sons are a wonderful legacy and represent the pinnacle of Spanish painting in the century known as the Golden Age. More than three centuries after they were created they are not just national but international treasures, and we are very fortunate to have them here.

“Whilst we are sad to see Joseph, Naphtali, Asher, Dan, Levi and Reuben leave, their departure represents not only the start of a bright new future for Auckland Castle, but a unique opportunity for these master works to be studied.”

Dr Chris Ferguson, Auckland Castle’s curatorial director, added: “We are thrilled to be working with major North American partners such as The Meadows Museum and Foundation, and The Frick Collection. Through their kind support, this collaborative project will allow us to learn much more about these Spanish artistic gems, and will showcase them to a new audience in the United States.

“This partnership marks one of the first steps in County Durham truly becoming the home of Spanish Art in the United Kingdom. International collaboration is fundamental to our ambitions as a new venue for the appreciation, research, and understanding, of the art and culture of the Hispanic world.

“We hope that these focused exhibitions of the art from County Durham will attract transatlantic visitors to Bishop Auckland over the coming years.”

The research and its publication, as well as the United States exhibitions, has been funded by The Meadows Foundation, with the technical study being supervised by Claire Barry, Director of Conservation at the Kimbell Art Museum.

Clare Baron said the research would ultimately enable the Zurbarán’s full story to be told when Auckland Castle reopens to the public in 2018.

Life-size reproductions of the six paintings will hang in the Long Dining Room alongside the remaining works of Jacob, Simeon, Judah, Zebulun, Issachar, Benjamin, and Gad, until the end of September when the Castle will close to allow the restoration work to begin in earnest.

The remaining seven portraits will themselves then be removed and head to the United States in October – only the third time the whole series has left the Castle since 1756.